Mold detecting device using sensor to measure ph of a surface

ABSTRACT

A mold sensor is configured with an enclosed chamber in which a nutrient-treated substrate is positioned. The mold sensor includes a sensing system that is configured to measure a property of the substrate that corresponds to a pH value of the substrate. A controller operates the sensing system and is programmed to detect a presence of mold growing in the chamber by estimating the pH value from the measured property.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application Ser.No. 62/787,140 filed Dec. 31, 2018, the disclosure of which is herebyincorporated in its entirety by reference herein.

TECHNICAL FIELD

This application generally relates to an integrated sensor for detectingmold in an environment.

BACKGROUND

Mold can be a serious problem in many environments. Prolonged exposureto mold can cause health issues. Excessive mold growth can stain ordegrade surfaces of a structure. Further, the presence of mold may beindicative of a moisture problem in the structure. Oftentimes, a moldproblem may exist for some time without detection. In some cases, themold growth is readily visible and can be detected by visual inspection.In many cases, mold is present but not readily visible to an observer.Ideally, it would be desirable to detect mold before it can cause healthor structure issues.

Mold spreads by releasing spores in the air. The mold spores may growwhen they land on a medium where conditions are suitable for growth. Theconditions suitable for growth include appropriate levels of nutrients,water, and pH balance. Mold spores that do not land on such a medium mayremain inactive and can be carried by air. Mold spores are found in mostair in some concentration. Problem areas may have a higher concentrationof mold spores.

A typical method of detecting mold is to collect a surface or air samplein an affected location. Particulate matter may be accumulated or placedon a microscope slide. An expert may view the slide through a microscopeto identify mold and determine the mold concentration and types of moldthat are present. These methods generally require taking the sample andsending the sample to a laboratory that has expertise in mold detection.Such processes tend to be labor intensive and rather expensive. Further,it can take some time to receive the results. The prior methods do notpermit continuous sampling of an area.

A mold sensor includes a housing defining a chamber and a substratetreated to promote mold growth and exposed within the chamber. The moldsensor includes a sensing device configured to measure a property of thesubstrate that corresponds to a pH value of the substrate. The moldsensor includes a controller programmed to receive measurements of theproperty from the sensing device, generate an estimated pH value of thesubstrate from the measurements, and output a signal indicative of moldgrowth on the substrate responsive to the estimated pH value beingassociated with mold growth.

The substrate may be treated with a pH indicator that changes color asthe pH value of the substrate changes due to mold growth. The propertymay be a color of the substrate and the sensing device may be a cameraconfigured to generate color images of the substrate, and the controllermay be further programmed to process the color images and generate theestimated pH value of the substrate based on the color derived from thecolor images. The property may be an impedance of the substrate and thesensing device may include a plurality of electrodes attached to thesubstrate, and the controller may be further programmed to generate theestimated pH value of the substrate based on the impedance between pairsof electrodes. The sensing device may include a sense electrode, areference electrode, and a working electrode attached to the substrate.The controller may be further programmed to supply a current to theworking electrode such that a voltage at the sense electrode remains ata predetermined voltage and generate the estimated pH value of thesubstrate based on the current. The controller may be further programmedto supply the current to maintain a pH value at a predetermined pHlevel.

A mold sensor includes a housing defining a chamber and a substratecoated with a hydrogel that includes nutrients to promote mold growthand exposed within the chamber. The mold sensor includes at least oneelectrical sense device including a sense electrode, a referenceelectrode, and a working electrode embedded in the hydrogel. The moldsensor includes a controller programmed to supply a current to theworking electrode such that a voltage at the sense electrode remains ata predetermined voltage and estimate a pH value of the hydrogel based onthe current.

The controller may be further programmed to output a signal indicativeof mold growth in the chamber based on changes in the estimate of the pHvalue. The controller may be further programmed to supply the current tomaintain the pH value at a predetermined pH level. The predetermined pHlevel may be configured to encourage growth of one or more predeterminedtypes of mold. The substrate may be segmented into a plurality of zonesand there may be at least one electrical sense device in each of thezones. The controller may be further programmed to maintain the pH valueof the zones at a different pH level. The controller may be furtherprogrammed to change the current to maintain the sense electrode at apredetermined reference voltage representing a predetermined pH value.The controller may be further programmed to generate a signal indicativeof a presence of mold growth responsive to the current exceeding apredetermined current.

A method includes supplying, by a controller, a current to a workingelectrode attached to a substrate coated with a hydrogel such that avoltage at a sense electrode attached to the substrate remains at apredetermined voltage. The method includes estimating, by thecontroller, a pH value of the hydrogel based on the current. The methodincludes outputting, by the controller, a signal indicative of moldgrowth on the hydrogel based on the pH value that is estimated.

The method may further include supplying the current to maintain the pHvalue of the hydrogel at a predetermined pH value. The predetermined pHvalue may be configured to encourage growth of one or more predeterminedtypes of mold on the hydrogel. The method may further include adjustingthe current based on a difference in voltage between the sense electrodeand a reference electrode attached to the substrate. The method mayfurther include measuring the current prior to mold growth to establisha baseline pH level.

SUMMARY

A mold detecting device includes a sensing device for measuring the pHof a surface on which mold is grown. In some configurations, the sensingdevice is an optical sensor configured to detect color and the surfaceis treated with a pH indicator that changes color as pH changes. In someconfigurations, the sensing device is an electrical sensor that measuresa change in electrical properties caused by a change in pH level. Insome configurations, the surface may be a hydrogel configured to changepH based on an applied current. A control device monitors the appliedcurrent to maintain the pH at a predetermined pH level. Changes in theapplied current are indicative of mold growth on the surface thatchanges the pH.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a single chamber mold sensor configuration with anintegrated sensor module.

FIG. 2 depicts a single chamber mold sensor configuration with amulti-piece sensor.

FIG. 3 depicts an alternative configuration of a single chamber moldsensor with an integrated sensor.

FIG. 4 depicts an alternative configuration of a single chamber moldsensor with a multi-piece sensor.

FIG. 5 depicts an example of a multi-chamber mold sensor configuration.

FIG. 6 depicts an example of a single chamber mold sensor configured toexpose a surface to airflow outside of the single chamber.

FIG. 7 depicts a second example of a single chamber mold sensorconfigured to expose a surface to airflow outside of the single chamber.

FIG. 8 depicts a growth surface including stripes of different nutrienttreatments.

FIG. 9 depicts a growth surface having alternating sections of surfacetypes.

FIG. 10 depicts a growth surface including regions of different nutrienttreatments.

FIG. 11 depicts an example of a tape-based surface exchange mechanism.

FIGS. 12A and 12B depict different views of a drum-based surfaceexchange mechanism.

FIG. 13A depicts an example of a disc-based surface exchange mechanism.

FIG. 13B depicts an example of disc configuration for the disc-basedsurface exchange mechanism.

FIG. 14 depicts a possible configuration for a capacitive-type sensorfor detecting mold on a growth surface.

FIG. 15 depicts a possible configuration for growth surface withintegrated electrical contacts.

FIG. 16 depicts an example of a growth surface with conductive strips.

FIG. 17 depicts an example of a roller-based electrical contact forinteracting with conductive strips of a growth surface.

FIGS. 18A and 18B depicts different views of an electrode-basedelectrical contact for interacting with conductive strips of a growthsurface.

FIG. 19 depicts an example of a growth surface configured to measure andcontrol a pH level of the growth surface.

FIG. 20 depicts a mold sensor system including mold sensors and acommunication network.

FIG. 21 depicts a flowchart for a possible sequence of operations foroperating the mold sensor.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described herein. It is to beunderstood, however, that the disclosed embodiments are merely examplesand other embodiments can take various and alternative forms. Thefigures are not necessarily to scale; some features could be exaggeratedor minimized to show details of particular components. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a representative basis forteaching one skilled in the art to variously employ the embodiments. Asthose of ordinary skill in the art will understand, various featuresillustrated and described with reference to any one of the figures canbe combined with features illustrated in one or more other figures toproduce embodiments that are not explicitly illustrated or described.The combinations of features illustrated provide representativeembodiments for typical applications. Various combinations andmodifications of the features consistent with the teachings of thisdisclosure, however, could be desired for particular applications orimplementations.

An improved way of detecting mold may be an integrated sensor devicethat can detect the presence of mold without having to send a sample toa laboratory. A further advantage of an integrated sensor is that themold sensor may be placed in a location to continuously monitor thelocation. This can generate an alert when mold becomes a problem. A moldsensor is disclosed herein that is configured to sample air and detect aconcentration of mold in the air. The mold sensor may be configured tocreate a small enclosed environment that is conducive to mold growth.Mold growth may be detected in a variety of ways.

This application first discloses general configurations and structuralelements for a mold sensing device. Specific mold sensing technologiesand strategies are then disclosed that are applicable to the generalconfigurations. Various operating modes and strategies are thendisclosed. A mold sensing system may incorporate a plurality of moldsensors. The mold sensor may be of a common design with communicationcapability. The mold sensing system may include a reference mold sensorand a target area mold sensor. The reference mold sensor may providemold concentration information that is expected in the environment(e.g., outdoors). The target mold sensor may provide mold concentrationinformation for an area of interest (e.g., basement, living space). Themold sensing system may incorporate results from multiple sensors toaccurately determine mold concentrations in the target area.

FIG. 1 depicts a diagram of a configuration for a first mold sensorconfiguration 100. The first mold sensor configuration 100 may include ahousing 102 that defines a chamber 103. The housing 102 may define abottom opening to allow a surface to be exposed within the chamber 103(e.g., housing 102 has no bottom). The housing 102 may be constructedfrom plastic, metal, and/or other suitable materials that do not outgasor are otherwise not conducive to mold/bacteria growth. Surfaces of thehousing 102 that are within the chamber 103 may be coated with a layerto avoid or inhibit mold growth (e.g., alkaline coating with pH>7).While shown as a cube, the shape of the housing 102 may be otherwiseshaped. The specific shape of the housing 102 may be dependent on othermechanisms that are coupled to the housing 102.

The first mold sensor configuration 100 may include an air entry portal104. The air entry portal 104 may be configured to define an airflowpath 106 into the chamber 103. In some configurations, the housing 102may define an opening to act as the air entry portal 104. In someconfigurations, the air entry portal 104 may be configured toselectively open and close. For example, a movable grate or door may beplaced over an opening defined by the housing 102. The movable grate ordoor may be electrically actuated by a solenoid into an open or closedposition. A spring mechanism may hold the movable grate in a normallyclosed position. The solenoid may be actuated by a control device 116.The movable grate or door may be electrically, magnetically, ormechanically operated. Some configurations may include an airflow sensor119 to determine airflow into the chamber 103. The airflow sensor 119may be electrically coupled to the control device 116. While not shownin all configurations, the airflow sensor 119 may be incorporated intothe other configurations that are described herein.

The control device 116 may be a controller that includes a processingunit and non-volatile and volatile memory. The controller may beprogrammed to perform various operations related to operating the moldsensor. The control device 116 may further include any electricalinterfaces for interacting with actuators and sensors that are part ofthe mold sensor. In addition, the control device 116 may include anetwork interface for accessing networks. The network interface may bewired and/or wireless. The network interface may provide a communicationpath for accessing the Internet/world-wide web. The control device 116may be mounted to the housing 102.

The first mold sensor configuration 100 may further include a growthsurface 112. The growth surface 112 may be a surface that is exposedwithin the chamber 103 and that is suitable for mold growth. In someconfigurations, the growth surface 112 may be exposed to air outside ofthe chamber 103. For example, the growth surface 112 may be exposed tothe environment outside of the chamber 103 for air sampling, followed bymoving the growth surface 112 into the chamber 103 for mold growth. Theair entry portal 104 may be configured to define the airflow path 106such that air is directed to flow toward the growth surface 112. Thegrowth surface 112 may be configured as a surface that is conducive tocapturing mold spores from the air. The growth surface 112 may beconfigured as a medium suitable to promote mold growth. The growthsurface 112 may be treated with nutrients that promote mold growth. Forexample, nutrients may include organic materials, salt, agar, and/orsugar. The growth surface 112 may also be configured to supply asufficient moisture content to encourage mold growth or may be packagedin a manner to retain the moisture content until usage. The growthsurface 112 may include anti-bacterial chemicals or treatments toprevent bacteria from growing. The growth surface 112 may be a tape, amembrane, or a filter. The tape, membrane, or filter may be treated withvarious substances to promote mold growth. The tape, membrane, or filtermay be air-permeable or non-permeable. One or more temperature andhumidity/moisture sensors may be integrated with the growth surface 112to allow monitoring of the mold growth environment.

The specific conditions for promoting mold growth may depend on the typeof mold to be grown. Different molds may prefer a different nutrientenvironment. The growth surface 112 may further includes regions (e.g.,stripes) that are configured to grow different types of mold. Forexample, each region of the growth surface 112 may be treated with adifferent nutrient mixture that promotes the growth of a different typeof mold. An advantage of this configuration is that the types of moldpresent may be identified by monitoring mold growth in each of theregions.

The first mold sensor configuration 100 may include a sensing device 110that is configured to sense mold growing on the growth surface. Theplacement of the sensing device 110 may be dependent on the type ofsensing that is performed. Further, the orientation of the sensingdevice 110 relative to the housing 102 may depend on the type of sensingdevice 110. For example, FIG. 1 depicts the sensing device 110 mountedat an angle relative to the housing 102. Some sensing deviceconfigurations may perform better when directed toward or through thegrowth surface 112. A variety of technologies are available for thesensing device 110. The sensing device 110 may be electrically connectedto the control device 116. The sensing device 110 may be containedwithin a single module that is coupled to the housing 102. Some sensorconfigurations (e.g., optical or audio) may utilize a source module anda receiver module. The sensing device 110 may integrate the source andreceiver modules into a single unit. In some configurations, the sensingdevice 110 may include multiple sensing devices of the same or differenttechnology that are placed in different positions within the housing102. Various configurations of the sensing device 110 are disclosedherein.

The first mold sensor configuration 100 may include a mold suppressor108 that is configured to destroy mold. The mold suppressor 108 may bemounted on a side of the housing 102. For example, the mold suppressor108 may be one or more ultraviolet (UV) light sources. For example, themold suppressor 108 may be a single UV light source or an army of UVlight sources. The UV light source may be a source illuminatingdivergent beam that can illuminate the entire growth surface 112 that isexposed in the chamber 103. The UV light source may be a UV source witha beam divergence component to enlarge the UV beam to illuminate theentire growth surface 112 that is exposed in the chamber 103. The moldsuppressor 108 may be a UV light source with a driver to sweep the UVlight source across the growth surface 112 that is exposed within thechamber. In addition, the mold suppressor 108 may be configured todestroy mold on other surfaces of the chamber 103 (e.g., inner-sidewalls) and the air entry port 104. The mold suppressor 108 may beelectrically actuated by the control device 116. The mold suppressor 108may be actuated for a predetermined period of time to destroy mold thathas grown. The control device 116 may activate the mold suppressor 108after completion of a measurement cycle to destroy mold that was grownduring the measurement cycle. The mold suppressor 108 may be operated todestroy mold within the chamber 103 to define a baseline conditionbefore starting a measurement cycle.

The first mold sensor configuration 100 may further include a surfaceexchange mechanism 114 that is configured to support the growth surface112 and facilitate exchange of the growth surface 112. In someconfigurations, the growth surface 112 may be fixed to the surfaceexchange mechanism 114. The surface exchange mechanism 114 may beconfigured to selectively couple to the housing 102. After a measurementcycle is completed, the growth surface 112 may be replaced to enableanother measurement cycle. The surface exchange mechanism 114 may beattached to and detached from the housing 102 to change the growthsurface 112 when desired. The housing 102 may define an opening on abottom surface to expose the growth surface 112 to the chamber 103 whenthe surface exchange mechanism 114 is coupled to the housing 102. Insome configurations, the housing 102 may be constructed without a bottomsurface.

In some configurations, the growth surface 112 may be movable and thesurface exchange mechanism 114 may be configured to move the growthsurface 112 to another position. The surface exchange mechanism 114 maybe configured to store portions of the growth surface 112 that are notcurrently exposed within the housing 102. The portions stored mayinclude an unused portion and a used portion. The surface exchangemechanism 114 may be configured to be electrically/mechanically actuatedand may be electrically coupled to the control device 116. Variousconfigurations of the surface exchange mechanism 114 are discussed inmore detail in subsequent sections herein. In some configurations, thesurface exchange mechanism 114 may include the capability toelectrostatically charge the growth surface 112 to improve the abilityto attract mold spores.

The first mold sensor configuration 100 may include one or more thermalcontrol elements 120 that are configured to change the temperature inthe chamber 103 to promote mold growth. Additional thermal controlelements may be embedded on, in, or below the growth surface 112. Thethermal control element 120 may be electrically coupled to the controldevice 116. The thermal control element 120 may include a thermoelectriccooling element. For example, the thermal control element 120 may be athermoelectric heat pump (e.g., Peltier device or heat pump). Thethermal control element 120 may include a heating element such as aresistive element. The thermal control element 120 may include aninfrared source (IR). The thermal control element 120 may be a singleelement or may be comprised of a plurality of thermal control elementspositioned at different locations in the chamber 103 to independentlycontrol the temperature in different areas of the chamber 103. In someconfigurations, the mold sensor may include a mechanism for adjustinghumidity within the chamber 103. Different environmental conditions(e.g., temperature) within the same nutrient zone may be used todistinguish between different types of mold. For example, a givennutrient zone exposed to different environmental conditions may createmultiple zones that favor growth of different types of mold. The thermalcontrol element 120 may be configured to create different temperatureconditions in different regions of the growth surface 112. For example,by placing the thermal control element 120 on one side of the chamber103, temperatures may increase or decrease as the distance from thethermal control element 120 increases. This may provide differentenvironmental conditions for different parts of the growth surface 112.

The first mold sensor configuration 100 may include a chamberenvironment sensor 118 that is configured to measure environmentalconditions within the chamber 103. The chamber environment sensor 118may be electrically connected to the control device 116. The chamberenvironment sensor 118 may include one or more temperature sensors, ahumidity sensor a pressure sensor and/or a gas sensor. A temperaturesensor may be positioned in a path of the airflow that enters thechamber 103. The chamber environment sensor 118 may be monitored atperiodic intervals to determine the status of conditions within thechamber 103.

An external environment sensing module 122 may be present to provideinformation about the environment external to the chamber 103. Theenvironmental sensing module 122 may include a temperature sensor,humidity sensor, pressure sensor, and/or gas sensor. The environmentalsensing module 122 may be electrically coupled to the control device116. The external environment sensing module 122 may be integrated withthe housing 102 or may be a separate module that communicates with thecontrol device 116. Communication between the control device 116 and theexternal environment sensing module 122 may be via a wirelesscommunication protocol (e.g., Bluetooth, Bluetooth LE, WiFi, optical).The environmental sensing module 122 may provide information onconditions surrounding or nearby the first mold sensor configuration 100that may influence mold growth. The control device 116 may be furtherconfigured to receive information from an external network (e.g.,Internet) to provide additional context for mold detection. The presenceand/or concentration of mold spores may vary depending on time of day,season, and environmental parameters. The control device 116 may collectthis additional information and utilize the information in the molddetection process. The control device 116 may use the information todetermine the conditions for initiating a measurement cycle. Forexample, during times of the year when mold spores are present in higherconcentrations, the control device 116 may initiate measurement cyclesmore often.

FIG. 2 depicts a second mold sensor configuration 200. The second moldsensor configuration 200 may be configured for sensors in which thesource and receiving modules are not integrated. The second mold sensorconfiguration 200 may include a sensor source module 210 and a sensorreceiving module 212. For example, in an optical sensing system, thesensor source module 210 may be a light source and the sensor receivingmodule 212 may be light sensor. The sending and receiving modules mayoperate cooperatively to detect mold within the chamber 103. The sensorsource module 210 and the sensor receiving module 212 may beelectrically coupled to the control device 116. In operation, thecontrol device 116 may activate the sensor source module 210 and receivesignals from the sensor receiving module 212.

In the configuration depicted, the sensor source module 210 is coupledto a side wall of the housing 102. The sensor receiving module 212 iscoupled beneath the growth surface 112. The sensor receiving module 212may be mounted to a frame or platform that is beneath the growth surface112. The sensor source module 210 and the sensor receiving module 212may be aligned to ensure that the sensor receiving module 212 canreceive signals from the sensor source module 210. In otherconfigurations, the positions of the sensor receiving module 212 and thesensor source module 210 may be reversed.

The first mold sensor configuration 100 may be described as having anintegrated mold sensing device. That is, the sensing device 110 is asingle module that is coupled to the housing 102. The second mold sensorconfiguration 200 may be described as having a two-part sensing device.The second mold sensor configuration 200 may be useful for sensingconfigurations that measure a characteristic that is transmitted throughthe growth surface 112.

The air entry port 104, mold suppressor 108, sensing device(s), thermalcontrol element 120, and chamber environment sensor 118 may be mountedin various configurations. The particular location selected may dependon packaging constraints of the housing and-or performanceconsiderations for mold detection. The location of the sensing device(s)may be selected depending on the type of sensing device being used. Forexample, a sensing device using optical sensors may be positioneddifferently than a sensing device configured to measure electricalproperties.

FIG. 3 depicts a third mold sensor configuration 300. The third moldsensor configuration 300 may include a housing 302 that defines achamber 303. The third mold sensor configuration 300 may include a sideair entry portal 304. The side air entry portal 304 may be configured tocreate an airflow path 306 into the chamber 303. In some configurations,the side air entry portal 304 may redirect the flow of air to divertairflow toward the growth surface 112. For example, the side air entryportal 304 may include angled slats or strips to redirect air flow. Insome configurations, the housing 302 may define an opening to act as theside air entry portal 304. In some configurations, the side air entryportal 304 may be configured to selectively open and close. For example,a movable grate or door may be placed over an opening defined by thehousing 302. The movable grate or door may be electrically actuated by asolenoid into an open or closed position. A spring mechanism may holdthe movable grate in a normally closed position. The solenoid may beactuated by the control device 116. The movable grate or door may beelectrically, magnetically, or mechanically operated.

The third mold sensor configuration 300 may include a top-mounted moldsuppressor 308. The top-mounted mold suppressor 308 may function asdescribed previously with reference to the mold suppressor 108 ofFIG. 1. The third mold sensor configuration 300 may include atop-mounted sensing device 310. The top-mounted sensing device 310 mayfunction as described previously with reference to the sensing device110 of FIG. 1. The top-mounted mold suppressor 308 and sensing device310 may be integrated into a single unit (e.g., a sensor/suppressormodule). An integrated device may facilitate assembly of the moldsensor.

The third mold sensor configuration 300 describes a configuration withdifferent air entry ports and sensor locations. The components maygenerally function as previously described.

FIG. 4 depicts a fourth mold sensor configuration 400. The fourth moldsensor configuration 400 may be configured for sensors in which thesource and receiving modules are not integrated. The fourth mold sensorconfiguration 400 may include a top-mounted sensor source module 410 anda sensor receiving module 412. For example, in an optical sensingsystem, the top-mounted sensor source module 410 may be a light sourceand the sensor receiving module 412 may be light sensor. The sending andreceiving modules may operate cooperatively to detect the mold. Thetop-mounted sensor source module 410 and the sensor receiving module 412may be electrically coupled to the control device 116. In operation, thecontrol device 116 may activate the top-mounted sensor source module 410and receive signals from the sensor receiving module 412.

In the configuration depicted, the top-mounted sensor source module 410is coupled to a top wall or ceiling of the housing 302. The sensorreceiving module 412 is coupled beneath the growth surface 112. Thetop-mounted sensor source module 410 and the sensor receiving module 412may be aligned to ensure that the sensor receiving module 412 canreceive signals from the top-mounted sensor source module 410. Thetop-mounted mold suppressor 308 and top mounted sensor source 410 may beintegrated into a single unit (e.g., a sensor source/suppressor module).An integrated device may facilitate assembly of the mold sensor. Inother configurations, the positions of the sensor source module 410 andthe sensor receiving module 412 may be reversed.

FIG. 5 depicts a dual-chamber mold sensor configuration 500. Thedual-chamber mold sensor configuration 500 may include a dual-chamberhousing 502 that includes a dividing wall 507 that defines a firstchamber 503 and a second chamber 505. The first chamber 503 may be usedfor growing mold on a portion of a growth surface 512 that is exposedwithin the first chamber 503.

The dual-chamber mold sensor configuration 500 may include an air entryportal 504. The air entry portal 504 may be configured to define anairflow path 506 into the first chamber 503. In some configurations, thedual-chamber housing 502 may define an opening to act as the air entryportal 504. In some configurations, the air entry portal 504 may beconfigured to selectively open and close. For example, a movable grateor door may be placed over an opening defined by the dual-chamberhousing 502. The movable grate or door may be electrically actuated by asolenoid into an open or closed position. A spring mechanism may holdthe movable grate in a normally closed position. The solenoid may beactuated by a control device 116. The movable grate or door may beelectrically, magnetically, or mechanically operated.

The dual-chamber mold sensor configuration 500 may include one or moremold sensing devices 510 that are configured to sense mold growing onthe growth surface 512. The placement of the sensing device 510 may bedependent on the type of sensing that is performed. A variety oftechnologies are available for the sensing device 510. The sensingdevice 510 may be electrically connected to the control device 116. Thesensing device 510 may be contained within a single module that iscoupled to the housing 502. Various configurations of the sensing device510 are disclosed herein.

The dual-chamber mold sensor configuration 500 may include one or moresensor receiving modules 511. The sensor receiving modules 511 may bepresent in configurations in which the sensing device 510 acts as asource. The dual-chamber mold sensor configuration 500 may be configuredto have a single mold sensing device 510A configured to detect moldgrowth in the first chamber 503. The dual-chamber mold sensorconfiguration 500 may be configured to have a single mold sensing device510A and a single sensor receiving module 511A configured to detect moldgrowth in the first chamber 503. The dual-chamber mold sensorconfiguration 500 may be configured to have a single mold sensing device510B configured to detect mold growth in the second chamber 505. Thedual-chamber mold sensor configuration 500 may be configured to have asingle mold sensing device 510B and a single sensor receiving module511B configured to detect mold growth in the second chamber 505. Thedual-chamber mold sensor configuration 500 may also be configured tohave mold sensing devices 510A/511A, 510B/511B in both the first chamber503 and the second chamber 505.

The dual-chamber mold sensor configuration 500 may include a moldsuppressor 508 that is configured to destroy mold. The mold suppressor508 may be mounted on a side or top of the housing 502. The moldsuppressor 508 may be configured to destroy mold in the second chamber505. The mold suppressor 508 may function as previously describedherein. Further, the mold suppressor 508 may be integrated with the moldsensing device 510 as previously described herein.

The dual-chamber mold sensor configuration 500 may further include asurface exchange mechanism 514 that is configured to move the growthsurface 512 to another position. For example, the surface exchangemechanism 514 may include one or more rollers that are configured tomove the growth surface 512. The growth surface 512 that is exposedwithin the first chamber 503 may be referred to as an active growthsurface. The active growth surface may be the surface on which mold isto be grown or is growing. The portion of the growth surface 512 that isexposed within the second chamber 505 may be referred to as the usedsurface. The used surface may the surface on which mold has already beengrown. The surface exchange mechanism 514 may be configured to advancethe growth surface 512 to provide a new active growth surface within thefirst chamber 503. The surface exchange mechanism 514 will be describedin more detail herein. Another configuration may be in which the growthsurface 512 is exposed to air in the first chamber 503 and then moved tothe second chamber 505 for growth, measurement, and destruction (e.g.,similar to single chamber configurations).

The dual-chamber mold sensor configuration 500 may include a thermalcontrol element 520 that is configured to change the temperature in thefirst chamber 503 to promote mold growth. Additional thermal controlelements may be embedded on, in, or below the growth surface 512. Thethermal control element 520 may be a thermoelectric element that iselectrically driven by the control device 116. The dual-chamber moldsensor configuration 500 may also include a similar thermal controlelement in the second chamber 505. The thermal control element 520 mayfunction as described previously for the similar element of the otherconfigurations.

The dual-chamber mold sensor configuration 500 may include a chamberenvironment sensor 518 that is configured to measure environmentalconditions within the first chamber 503. The chamber environment sensor518 may be electrically connected to the control device 116. The chamberenvironment sensor 518 may include a temperature sensor, a humiditysensor, a pressure sensor, and/or a gas sensor. The chamber environmentsensor 518 may be monitored at periodic intervals to determine thestatus of conditions within the first chamber 503. The dual-chamber moldsensor configuration 500 may also include a similar environment sensorin the second chamber 505.

The dual-chamber mold sensor configuration 500 provides separatechambers for mold growth and destruction. An advantage of thedual-chamber mold sensor configuration 500 is that the sensor can becontinually used for mold sensing. The single chamber configurationsgrow and destroy mold in the same chamber so that during the molddestruction phase a new sample may not be initiated. In someconfigurations, the mold sensor may utilize more than two chambers. Amulti-chamber mold sensor configuration may also be used. For example,different chambers may be configured to be operated to differentenvironmental parameters to create a growth environment for differenttypes of mold.

The general operation of the dual-chamber mold sensor configuration 500may be to expose a portion of the growth surface 512 in the firstchamber 503. The air entry portal 504 may be opened at a predeterminedtime for a predetermined amount of time and then closed. The controldevice 116 may operate the thermal control element 520 and monitor thechamber environment sensors 518 to produce an environment conducive tomold growth. The control device 116 may monitor signals from the sensingdevice 510/511 to determine if mold is present. Upon completion of themeasurement cycle, the control device 116 may activate the surfaceexchange mechanism 514 to move the growth surface 512 such that theexposed portion in the first chamber 503 moves to the second chamber505. A new active growth surface may be moved into the first chamber 503to enable a new measurement cycle.

The control device 116 may then operate the mold suppressor 508 todestroy the mold on the growth surface 512. In configurations with amold sensing device (e.g., 510B/511B) in the second chamber 505, thecontrol device 116 may monitor the corresponding signals for signs ofmold destruction.

FIG. 6 depicts a first single-chamber with external exposureconfiguration 600. The single-chamber/external exposure configuration600 may incorporate a single chamber that is configured to grow anddestroy mold. The single-chamber/external exposure configuration 600 mayinclude a housing 602 that defines a chamber 603. Thesingle-chamber/external exposure configuration 600 further includes agrowth surface 612. The growth surface 612 may be configured to beexposed to airflow 606 outside of the chamber 603.

The single-chamber/external exposure configuration 600 further includesa surface exchange mechanism 614 that is configured to move the growthsurface 612 into different positions. An exposed portion 630 of thegrowth surface 612 may be exposed to airflow 606 outside of the chamber603. The exposed portion 630 may be subjected to airflow 606 for apredetermined amount of time to collect mold spores that are present inthe airflow 606. The surface exchange mechanism 614 may be actuated tomove the exposed portion 630 into the chamber 603. As such, anadditional previously unexposed portion of the growth surface 612 may bepositioned to be the exposed portion 630. The surface exchange mechanism614 is described in additional detail herein.

The single-chamber/external exposure configuration 600 may include amold sensing device 610 that is configured to sense mold growing on thegrowth surface 612. The placement of the sensing device 610 may bedependent on the type of sensing that is performed. A variety oftechnologies are available for the sensing device 610. The sensingdevice 610 may be electrically connected to the control device 116. Thesensing device 610 may be contained within a single module that iscoupled to the housing 602. Various configurations of the sensing device610 are disclosed herein. The single-chamber/external exposureconfiguration 600 may include a sensor receiving module 611. The sensorreceiving module 611 may be present in configurations in which thesensing device 610 is configured as a source. The sensor receivingmodule 611 may be positioned below the portion of the growth surface 612that is within the chamber 603.

The single-chamber/external exposure configuration 600 may include amold suppressor 608 that is configured to destroy mold in the chamber603. The mold suppressor 608 may be mounted on a side or top of thehousing 602 (depicted on top). The mold suppressor 608 may function aspreviously described herein. Further, the mold suppressor 608 may beintegrated with at least a portion of the mold sensing device 610 aspreviously described herein.

The first single-chamber/external exposure configuration 600 may includea thermal control element 620 that is configured to change thetemperature in the chamber 603 to promote mold growth. Additionalthermal control elements may also be embedded on, in, or below thegrowth surface 612. The thermal control element 620 may be athermoelectric element that is electrically driven by the control device116. The single-chamber/external exposure configuration 600 may includea chamber environment sensor 618 that is configured to measureenvironmental conditions within the chamber. The thermal control element620 may operate as described herein.

The first single-chamber with external exposure configuration 600 ischaracterized in part by the trajectory of the growth surface 612. Asdepicted, the growth surface 612 within the chamber 603 is oriented atan angle of ninety degrees in relation to the exposed growth surface630. The angle is not limited to ninety degrees. The firstsingle-chamber with external exposure configuration 600 allows a moldmeasurement to take place while another air sample is being exposed tothe airflow 606.

FIG. 7 depicts a second single-chamber with external exposureconfiguration 700. The single-chamber/external exposure configuration700 may incorporate a single chamber that is configured to grow anddestroy mold. The single-chamber/external exposure configuration 700 mayinclude a housing 702 that defines a chamber 703. Thesingle-chamber/external exposure configuration 700 further includes amovable growth surface 712. The movable growth surface 712 may beconfigured to be exposed to airflow 706 outside of the chamber 703.

The single-chamber/external exposure configuration 700 further includesa surface exchange mechanism 714 that is configured to move the growthsurface 712 into different positions. An exposed portion 730 of thegrowth surface 712 may be exposed to airflow 706. The exposed portion730 may be subjected to airflow 706 for a predetermined amount of timeto collect mold spores that are present in the airflow 706. The surfaceexchange mechanism 714 may be actuated to move the exposed portion 730into the chamber 703. As such, another portion of the growth surface 712may be positioned to be the exposed portion 730. The surface exchangemechanism 714 is described in additional detail herein.

The single-chamber/external exposure configuration 700 may include amold sensing device 710 that is configured to sense mold growing on thegrowth surface 712. The placement of the sensing device 710 may bedependent on the type of sensing that is performed. A variety oftechnologies are available for the sensing device 710. The sensingdevice 710 may be electrically connected to the control device 116. Thesensing device 710 may be contained within a single module that iscoupled to the housing 702. Various configurations of the sensing device710 are disclosed herein. The single-chamber/external exposureconfiguration 700 may include a sensor receiving module 711. The sensorreceiving module 711 may be present in configurations in which thesensing device 710 acts as a source. The sensor receiving module 711 maybe positioned below the growth surface 712 that is within the chamber703.

The single-chamber/external exposure configuration 700 may include amold suppressor 708 that is configured to destroy mold. The moldsuppressor 708 may be mounted on a side or top of the housing 702(depicted on top). The mold suppressor 708 may be configured to destroymold in the chamber 703. The mold suppressor 708 may function aspreviously described herein. Further, the mold suppressor 708 may beintegrated with at least a portion of the mold sensing device 710 aspreviously described herein.

The first single-chamber/external exposure configuration 700 may includea thermal control element 720 that is configured to change thetemperature in the chamber 703 to promote mold growth. Additionalthermal control elements may be embedded on, in, or below the growthsurface 712. The thermal control element 720 may be a thermoelectricelement that is electrically driven by the control device 117. Thesingle-chamber/external exposure configuration 700 may include a chamberenvironment sensor 718 that is configured to measure environmentalconditions within the chamber.

The second single-chamber with external exposure configuration 700 maybe characterized in part by the trajectory of the growth surface 712. Asdepicted, the growth surface 712 within the chamber 703 is oriented inthe same plane in relation to the exposed growth surface 730. The secondsingle-chamber with external exposure configuration 700 may be mountedat any angle relative to the airflow 706. The sensor may be mounted sothat air impacts the exposed growth surface 730 at a predeterminedangle.

The mold sensor configurations disclosed herein may utilize a surfaceexchange mechanism that is configured to exchange a portion of thegrowth surface that is within the detection chamber. In addition, thesurface exchange mechanism may be configured to move an exposed growthsurface into the detection chamber. The growth surface or medium may beconfigured in a variety of ways. The growth medium may be a film or tapethat is coated to create a sticky or tacky surface. The sticky surfaceaids in attracting particles such as mold spores. In addition, thesurface of the film or tape may be coated with nutrients for moldgrowth. The surface of the film or tape may be coated with anantibacterial coating to prevent bacteria growth.

Different types of mold may favor different nutrients for growth. Thegrowth medium may be configured to encourage different types of mold togrow. FIG. 8 depicts a possible configuration of a growth medium 800.The growth medium 800 may include a substrate material 812. For example,the substrate material 812 may be a film, membrane, or tape. Thesubstrate material 812 may be made of plastic, fabric or other material.In various configurations, the substrate material 812 may be formed as astrip, a drum, or a disc. A plurality of test sections 802 may bedefined on the substrate material 812. The test section 802 may bedefined as an area or surface of the growth medium 800 that can beexposed within the chamber of the mold sensor. The test sections 802 maybe characterized by a width 816 and a length 814. The width 816 andlength 814 may correspond to the dimensions of the chamber or dimensionsof an opening for exposing the test section 802 within the chamber. Thetest section 802 may be repeated continuously on the substrate material812. During operation of the mold sensor, the test section 802 may beexposed to air and processed through a measurement cycle. The remainingtest sections defined on the substrate material 812 may be enclosed bythe surface exchange mechanism.

The test section 802 may be segmented into a plurality of stripes. Forexample, a first stripe 804, a second stripe 806, a third stripe 808,and a fourth stripe 810 may be defined on the test section 802. Each ofthe stripes may have a coating that favors the growth of a differenttype of mold. For example, the first stripe 804 may include a firstnutrient coating favorable for growing a first mold type. The secondstripe 806 may include a second nutrient coating favorable for growing asecond mold type. The third stripe 808 may include a third nutrientcoating favorable for growing a third mold type. The fourth stripe 810may include a fourth nutrient coating favorable for growing a fourthmold type. Within each stripe, different environmental conditions (e.g.,temperature) may be applied during a measurement cycle by operation ofthe thermal control element. Within each stripe, different environmentalsensors (e.g., temperature, humidity, pH) may be embedded on, in, orunder the stripe to monitor the conditions that promote mold growth. Thesensor information may be used to back-calculate the mold sporeconcentration in the air.

The segmentation of the test section 802 allows the mold sensor toefficiently detect the presence of different types of molds. Further,different stripe combinations may be produced depending on the types ofmold expected to be present in the environment at a time of the test.Test sections having a single nutrient coating may not efficientlydetect all types of mold. A further advantage of the stripes is that themold sensor can provide a more detailed report on the types of mold thatare present. By sensing the presence and/or concentration of mold ineach of the stripes, a more detailed report can be provided.

FIG. 9 depicts another possible configuration for a growth medium 900.The growth medium 900 may be comprised of alternating growth areasdefined on a substrate. The growth medium 900 may include a first growtharea 902. Adjacent to the first growth area 902 may be a non-growth area904. A second growth area 906 may be defined adjacent to the non-growtharea 904. The pattern of growth areas and non-growth areas may berepeated for the entire length of the growth medium 900. The non-growtharea 904 may be an area that is configured to avoid mold growth (e.g.,not coated or having a coating with a high pH value). The non-growtharea 904 may be an area that is not sticky or tacky. The non-growth area904 may be configured to provide a buffer between the first growth area902 and the second growth area 906. Each of the areas may becharacterized by a width 910 and a length 908. The width 910 and length908 may correspond to the dimensions of the chamber or dimensions of anopening for exposing the growth area 902 within the chamber. Thedimensions of each alternating area may be similarly defined.

The alternating growth medium configuration 900 may be useful inconfigurations in which the area exposed to the air is outside of thechamber. In such configurations, continuous mold detection may not bedesired. The non-growth area 904 may be positioned in the air-exposedregion without concern that mold spores will adhere to the surface. Whenready to perform a measurement cycle, the growth medium 900 may beadvanced by the surface exchange mechanism to expose the second growtharea 906 to air before advancing into the chamber. While the secondgrowth area 906 is exposed to air, the non-growth area 904 may be withinthe chamber. Note that the first growth area 902 and the second growtharea 906 may include stripes as described with reference to FIG. 8.

FIG. 10 depicts an alternative configuration for a growth medium 1000.The growth medium 1000 may include a substrate material 1004. Forexample, the substrate material 1004 may be a film, membrane, or tape.The substrate material 1004 may be made of plastic, fabric or othermaterial. In various configurations, the substrate material 1004 may beformed as a strip, a drum, or a disc. A plurality of test sections 1002may be defined on the substrate material 1004. The test section 1002 maybe defined as an area or surface of the growth medium 1000 that can beexposed within the chamber of the mold sensor. The test sections 1002may be characterized by a width 1018 and a length 1016. The width 1018and length 1016 may correspond to the dimensions of the chamber ordimensions of an opening for exposing the test section 1002 within thechamber. The test section 1002 may be repeated continuously on thesubstrate material 1004. During operation of the mold sensor, the testsection 1002 may be exposed to air and processed through a measurementcycle. The remaining test sections defined on the substrate material1004 may be enclosed by the surface exchange mechanism.

The test section 1002 may define one or more growth regions. Forexample, a first growth region 1006, a second growth region 1008, athird growth region 1010, and a fourth growth region 1012 may bedefined. Each of the growth regions may have a coating or treatment thatfavors the growth of a different type of mold. For example, the firstgrowth region 1006 may be treated with a first nutrient coatingfavorable for growing a first mold type. The second growth region 1008may be treated with a second nutrient coating favorable for growing asecond mold type. The third growth region 1010 may be treated with athird nutrient coating favorable for growing a third mold type. Thefourth growth region 1012 may be treated with a fourth nutrient coatingfavorable for growing a fourth mold type. The test section 1002 mayfurther include a non-growth area 1014. The non-growth area 1014 may bedefined as the area within the test section 1002 that is between thegrowth regions. The non-growth area 1014 may be an area of the substratematerial 1004 that is not treated to promote mold growth. The growthregions are depicted as squares but may be shaped differently. Forexample, the growth regions could be circular or rectangular. Further,while the pattern is shown as generally symmetric, the pattern could benon-symmetric. The test section 1002 may be repeated continuously on thesubstrate material 1004. During operation of the mold sensor, the testsection 1002 may be exposed to air and processed through a measurementcycle. The remaining test sections defined on the substrate material1004 may be enclosed by the surface exchange mechanism.

The test section 1002 may define a pattern that is repeated on thesubstrate material 1004. The pattern may repeat at a distance that isapproximately the length 1016 of the test section 1002. Each of thegrowth regions may favor the growth of a specific type of mold. Thedivision of the test section 1002 allows the sensor to efficientlydetect the presence of different types of molds. Further, differentgrowth region combinations may be produced depending on the types ofmold expected to be present in the environment at a time of the test. Afurther advantage of the different growth regions is that the moldsensor can provide a more detailed report on the types of mold that arepresent. By sensing the presence and/or concentration of mold in each ofthe growth regions, a more detailed report can be provided. Thenon-growth area 1014 may be useful for sensor calibration. Since mold isnot expected to grow on the non-growth area 1014, the mold sensor mayutilize this area to calibrate the sensing device.

Features of each of the growth surface configurations may be combined todefine additional growth surfaces. For example, the configurations ofthe FIG. 8 and FIG. 10 may include alternating regions that permit moldgrowth and prevent mold growth. The particular features selected for thegrowth surface may depend upon the mold sensor configuration. The growthsurface configurations, while depicted as strips, may be formed on asurface of a drum or a disc in a corresponding manner.

The mold sensor configurations may include a surface exchange mechanism.In some configurations, the surface exchange mechanism may be configuredas a single use cartridge that can be installed or removed from the moldsensor. The single-use surface exchange mechanism may include a fixedgrowth surface that is exposed in the chamber when the mechanism isattached to the mold sensor housing.

The surface exchange mechanism may also be configured to advance thegrowth surface in relation to the chamber. The surface exchangemechanism may be electrically controlled by the control device 116. Thesurface exchange mechanism may be configured to store a predefinedamount of growth surface that may be fed into the chamber for ameasurement cycle. The surface exchange mechanism may also be configuredto stored used growth surface that has been processed through ameasurement cycle.

FIG. 11 depicts a side view of a possible configuration of a tape-basedsurface exchange mechanism 1100 that is configured to advance a tape,membrane, or film. The tape-based surface exchange mechanism 1100 mayinclude a tape housing 1104. The tape housing 1104 may define aused-tape chamber 1114 and an unused-tape chamber 1116. The housing 1104may include a dividing wall 1118 between the used-tape chamber 1114 andthe unused-tape chamber 1116. The tape housing 1104 may be configured tocouple to a growth chamber housing 1102 that defines a growth chamber1103.

The tape-based surface exchange mechanism 1100 may include a reel orspool 1108 that rotates about an axis. The tape-based surface exchangemechanism 1100 may include a driven reel or spool 1106 that is driven byan electrical drive unit. The electrical drive unit may be an electricmotor having a shaft connected to an axis of the driven spool 1106. Insome configurations, the electrical drive unit may include an electricmotor coupled to the driven spool 1106 through one or more gears. Insome configurations, a manual crank assembly may be attached to drivenspool 1106 to permit manual advancement of the tape. The tape-basedsurface may be packaged such that the initial parameters (e.g., moisturelevel) of the tape are maintained until usage. For example, the exchangemechanism 1100 may include a liner or encapsulation that preventsmoisture from evaporating from the tape-based surface before usage. Theencapsulation may also prevent contamination of the tape-based surfacebefore usage.

A length of unused tape 1110 or film may be wrapped around the spool1108. The unused tape/film 1110 may be configured as a growth surface aspreviously described herein. The unused tape 1110 may be defined as thatportion of the tape that has not been advanced to the growth chamber1103. An end of the unused tape 1110 may be attached to the spool 1108.The tape may further include an active test surface 1122 that is definedas that portion of the tape that is positioned within the growth chamber1103. The tape may further include a length of used tape 1112 or filmthat may be defined as that portion of the tape that has been processedthrough a measurement cycle in the growth chamber 1103. An end of theused tape 1112 may be attached to the driven spool 1106.

The tape housing 1104 may define a separating surface 1120 that isconfigured to separate the unused tape 1110 and used tape 1112 from thegrowth chamber 1103. The separating surface 1120 may define slots oropenings through which tape may pass through. The tape-based surfaceexchange mechanism 1100 may further include a first guide roller 1124that is configured to direct unused tape 1110 from the unused-tapechamber 1116 into the growth chamber 1103. The tape-based surfaceexchange mechanism 1100 may further include a second guide roller 1126that is configured to direct tape (the active test surface 1122) intothe used-tape chamber 1114. The first guide roller 1124 and the secondguide roller 1126 may be coupled to the separating surface 1120 by abracket. In some configurations, the bracket may include a compliantcomponent that is configured to apply an amount of pressure to press therollers against a bottom surface of the mold sensor housing 1102 to aidin sealing the chamber 1103 from outside air and/or to improveelectrical contact between the tape and control device 116. A length ofthe first guide roller 1124 and the second guide roller 1126 may bedefined by a width of the tape.

Unused tape (such as described by FIGS. 8-10) may be wrapped or spooledon the spool 1108. The tape may be routed via the first guide roller1124 and the second guide roller 1126 so that an end may be attached tothe driven spool 1106. The mold measurement cycle may be performed usingthe active test surface 1122 that is exposed within the growth chamber1103. Upon completion of a measurement cycle, the driven spool 1108 maybe rotated by the electrical drive mechanism. The driven spool 1108 maybe driven to advance the portion of the tape that is the active testsurface 1122 into the used-tape chamber 1114. By rotating the drivenspool 1108 the tape will be advanced and wrap around the driven spool1106. The rotation causes unused tape 1110 to unwind from the spool 1108and advance into the growth chamber 1103 as the new active test surface1122. The total length of the tape may be configured to perform apredetermined number of measurements.

In some configurations, the used-tape chamber 1114 may containencapsulations and/or chemicals for inhibiting mold growth. This canprevent mold from growing in the unused-tape chamber 1116 and ensurethat mold that was grown during the measurement is further destroyed. Insome configurations, the unused-tape chamber 1116 may containencapsulations and/or chemicals to maintain the unused tape 1110 forlater use. For example, the encapsulations and/or chemicals may beconfigured to prevent the unused tape 1110 from becoming dry ornon-sticky which could negatively impact the measurement effectiveness.

The tape-based surface exchange mechanism 1100 may be implemented as acartridge that contains a predetermined length of tape or film. Thecartridge may be user replaceable. The cartridge may be disposable afterusage. In some configurations, the tape or film may be replaceablewithin the cartridge.

In some configurations, the tape or growth surface may include notchesalong one or both sides of the tape. For example, a notch may be placedto identify each test section of the tape. An optical sensor may bepositioned to provide a signal when the notch appears between the sourceand receiver. The control device 116 may use the signal to properlyposition the tape so that a test section is properly exposed in thechamber. The sensor may also be used to measure the amount of tape thathas been used. For example, the optical sensor may be used to count thenotches. Knowing the distance between notches and/or a total number ofnotches on the tape, the control device 116 may compute the amount oftape used and/or the amount of tape remaining and communicate the valuesto the user. The control device 116 may compute the number ofmeasurement cycles remaining based on the amount of tape remaining.

FIGS. 12A and 12B depict different views of a drum-based surfaceexchange mechanism 1200. The drum-based surface exchange mechanism 1200may include a drum 1204. The drum 1204 may be cylindrically-shaped. Insome configurations, the drum 1204 may be solid. In some configurations,the drum 1204 may be hollow with structural elements at each end tosupport and facilitate rotation of the drum 1204. The drum 1204 may berotated by an electric motor 1206 having a shaft coupled to a centralaxis of the drum 1204. The drum 1204 may include a growth surface 1208that may be defined as the area exposed within a growth chamber of amold sensor housing 1202. The drum 1204 may include an unexposed surface1203 that may be defined as the surface of the drum 1204 that is notexposed in the growth chamber of the mold sensor housing 1202. Thedrum-based surface exchange mechanism 1200 may include a housing (notshown) that is configured to attach to the mold sensor housing 1202 andsupport the electric motor 1206. The housing may further preventexposure of the drum surface to external air.

The drum 1204 may be divided into a number of surface segments 1210. Thesurface segments 1210 may be configured to fit within the growth chamberof the mold sensor housing 1202. A number of surface segments 1210 maydefine the number of measurement cycles that may be performed. Thesurface segments 1210 may be striped or subdivided as previouslydescribed in relation to tape configurations.

The drum 1204 may be a replaceable element such that when all surfacesegments 1210 have been used, a new drum 1204 may be installed. The olddrum may be discarded or recycled. In some configurations, the drumsurface may be a replaceable sheet or substrate. The used drum surfacesheet may be replaced by a new drum surface sheet.

The drum-based surface exchange mechanism 1200 may rotate by operationof the electric motor 1206. A measurement may be performed using thegrowth surface 1208 that is exposed in the chamber of the mold sensorhousing 1202. After the measurement cycle is completed, the electricmotor 1206 may be actuated to advance the drum 1204 to place a nextsurface segment 1210 into the growth chamber defined by the sensorhousing 1202. For example, in FIG. 12B, the current segment exposed inthe mold sensor housing 1202 is the growth surface 1208. Assuming aclockwise rotation, the surface segment 1210A may advance into the moldsensor housing 1202. The control device 116 may be configured to actuatethe electric motor 1206 for a predetermined duration calibrated torotate the drum 1204 an amount corresponding to one of the surfacesegments 1210. In other configurations, a sensor, such as apotentiometer or encoder, may be used as a feedback signal to measurethe amount of rotation and drive the electric motor 1206 accordingly. Insome configurations, a manual crank assembly may be attached to axis ofthe drum 1204 to permit manual advancement of the drum 1204.

FIG. 13A depicts a disc-based surface exchange mechanism 1300 foradvancing a disc 1308 to position a growth surface 1304 within a chamberformed by the sensor housing 1302. The disc-based surface exchangemechanism 1300 may include a disc housing 1306 that is configured toenclose the disc 1308. The disc 1308 may be configured to rotate about acentral axis. An electric motor 1310 may be coupled to the disc housing1306. A shaft of the electric motor 1310 may be coupled to the disc 1308to facilitate rotating the disc 1308.

In some configurations, the entire surface of the disc 1308 may betreated to promote mold growth. The disc 1308 may also be configured asdepicted in FIG. 13B. The disc 1308 may define growth areas 1312 thatare treated to promote mold growth as previously described herein. Thedisc 1308 may include a non-growth area 1314 that separates the growthareas 1312. The non-growth area 1314 may prevent mold growth fromspreading outside of the sensor housing 1302. The growth areas 1312 maybe divided into differently treated regions to promote growth ofdifferent types of mold as described previously herein.

The disc-based surface exchange mechanism 1300 may position the disc1308 by operation of the electric motor 1310. A measurement may beperformed using the growth surface 1304 that is exposed in the growthhousing 1302. After the measurement cycle is completed, the electricmotor 1310 may be actuated to rotate the disc 1308 to the next growtharea 1312. The control device 116 may be configured to actuate theelectric motor 1310 for a predetermined duration calibrated to rotatethe disc 1308 an amount corresponding to one of the growth areas 1312.In other configurations, a sensor, such as a potentiometer or encoder,may be used as a feedback signal to measure the amount of rotation anddrive the electric motor 1310 accordingly.

The mold sensor configurations include a sensing device configured todetect mold. The sensor may be electrically coupled to the controldevice 116. A variety of sensor technologies are adaptable to detectingmold growth within the housing. The types of sensors that may be usedinclude optical sensors, chemical sensors, biosensors, mechanicalsensors, audio sensors, and electrical sensors. The sensors may beconfigured to measure visual, mechanical, electrical, biological, and/orchemical properties associated with mold growth. The mold sensorconfigurations may include different types of sensors to detect thepresence of mold. Some sensor technologies may be better suited fordetecting the concentration of mold, while others may be suited fordetecting the presence of mold growth.

Referring to FIG. 1 as an example, the sensing device 110 may beimplemented in a variety of ways. Various configurations may rely ondifferent sensor technologies. The types of sensing device may be achemical/gas sensor, an electrical sensor, a biological sensor, anoptical sensor, a mechanical sensor, or an audio sensor. The type ofsensing device may depend on the type of properties associated with thepresence and/or concentration of mold that are to be detected. Thesensing device 110 may be configured to detect mold by measuring opticalproperties, electrical properties, biological properties, mechanicalproperties, and/or chemical properties. The different properties may bedetected by different types of sensors. For example, some chemicalproperties, such as pH, may be detected by optical and/or electricalsensors. Mechanical properties may be detected by electrical and/oroptical sensors. The sensing device may be characterized by the physicalproperty that it is attempting to measure and how it measures thephysical property.

Mold spores release microbial volatile organic compounds (mVOCs) as abyproduct during its metabolism. Mold spores may further releasemycotoxins during a second metabolism as an end product. Mold growth maybe detected by sensing these chemicals during the mold lifecycle. Thesensing device 110 may be a chemical sensor that is configured to sensethe changes in mVOCs or other chemicals associated with mold growth.

Mold may release alcohol, aldehyde, hydrocarbons, acids, ether, esters,ketones, terpenoids, sulfur, nitrogen and other compounds. The type ofchemicals released may depend upon the type of mold that is growing. Thesensing device 110 may be any type of chemical sensor that can detectthese compounds. For example, the sensing device 110 may be anelectrochemical gas sensor or a metal oxide gas sensor that isconfigured to detect these compounds. In some configurations, thesensing device 110 may include a plurality of chemical sensors that areeach configured to measure a specific chemical compound.

For example, the sensing device 110 may be a solid-state chemiresistorsensor that changes resistance in response to exposure to certainchemical compounds. The control device 116 may be programmed to estimatea gas concentration by measuring the resistance of the chemiresistorsensor. The control device 116 may include a voltage divider network andan analog-to-digital (A2D) converter to measure a voltage across thechemiresistor sensor. The control device 116 may store a table or tablesthat map voltage and/or resistance values to gas concentrations. Thecontrol device 116 may be configured to generate a warning or alarmresponsive to the gas sensor signal being indicative of moldconcentrations exceeding a threshold. For example, the warning may begenerated when the mold concentration exceeds a reference concentrationby more than a predetermined amount.

The control device 116 may store data that relates the chemical sensormeasurements to mold growth. The data may be experimentally derived fromtesting. The stored data may indicate gas types and levels duringdifferent phases of mold growth. In addition, the stored data mayinclude a gas profile for different types of mold. The control device116 may sample the chemical/gas sensor over time and compare the resultsto the stored data to further identify a type of mold, concentration ofmold, or growth phase of the mold. In addition, the initialconcentration of mold before mold growth may be determined byback-calculating and estimating the amount of growth based on data thatmay be experimentally derived from testing.

Mold growth may also change the properties of the growth medium as themold grows. Common mold types such as Aspergillus and Penicilliumfamilies shift the pH of the growth surface 112 towards acidity. Thesensing device 110 may be configured to sense a change in pH caused bymold growth. A first technique for detecting the pH of the growthsurface 112 includes adding a universal pH indicator solution to thegrowth surface 112. The universal pH indicator may change in color asthe pH of the growth surface 112 changes. The nutrient treatment for thegrowth surface 112 may include the universal pH indicator solution. Thesensing device 110 may be configured to detect color changes of thegrowth surface 112 that are associated with the pH changes. In someconfigurations, the sensing device 110 may be a camera that provides acolor image of the growth surface 112. For example, the camera may be acharge-coupled device (CCD) configured to provide a digital image of thegrowth surface 112. The control device 116 may be configured toimplement image processing algorithms to determine changes in color ofthe growth surface 112. The sensing device 110 may be an optical sensingdevice that is configured to output an electromagnetic wave (e.g.,light) and receive a reflected wave from the growth surface 112.

The color change caused by pH changes may be detected by changes in theoptical properties such as adsorption, reflection, scattering, color,and/or fluorescence. The properties may be detected with an opticalsensing system, an imaging system, or a camera system. For example, theoptical sensing system may be configured to provide data regarding colorof the mold growing on the surface. The control device 116 may beprogrammed to process the optical data including color information toidentify a color of the mold growth or substrate. The color informationmay be indicative of mold growing on the substrate. For example, achange in pH of the substrate may be identified by a change from abaseline color to a predetermined color. The predetermined colorsindicative of mold growth may be derived from experiments.

As shown for example in FIG. 2, the sensing system may incorporate asensor source module 210 and the sensor receiving module 212. While FIG.2 depicts the sensor receiving module 212 being on the opposite side ofthe growth surface 112 relative to the sensor source module 210, thesensor receiving module 212 may be placed on the same side of the growthsurface 112 as the sensor source module 210.

The sensor source module 210 may be a light source (or electromagneticwave source) and the sensor receiving module 212 may be a photodetector.For example, the photodetector may be placed below the growth surface112. The light source may be activated to produce an electromagneticwave in the chamber 103 to illuminate/irradiate the growth surface 112.Electromagnetic waves passing through the growth surface 112 may changewavelength based on the color of the growth surface 112. Thephotodetector (sensor receiving module 212) may receive theelectromagnetic waves and generate an electrical signal. Thephotodetector may be configured to detect different wavelengths ofelectromagnetic waves so that different colors may be detected. In someconfigurations, multiple photodetectors (e.g., photodetector array) maybe implemented with each photodetector tuned for a given wavelengthrange.

The optical sensing systems, imaging systems or camera systems mayinclude both the sensor source module 210 (e.g., optical source, LED,laser) and the sensor receiving module 212 (e.g., optical sensor,photodiode, photodetector, imager, camera). In some configurations, theoptical source may be a source illuminating divergent beam configured toilluminate a large area or entire area of the growth surface 112 withinthe chamber 103. The optical source may be a light source combined withbeam divergence component that diverges the beam to illuminate a largearea or entire area of the growth surface 112 within the chamber 103.The optical sensor may be an array of photodiodes or a camera that isconfigured to receive electromagnetic waves reflected or scattered fromand/or transmitted through the growth surface 112. In thisconfiguration, the optical property changes of the entire growth surface112 can be collected at the same time. The sensor source module 210 maybe driven by one or more input signals generated by the control device116. The sensor receiving module 212 may provide optical data that isindicative of one or more optical properties to the control device 116.The optical data may be provided as one or more electrical signals. Insome examples, the optical data may include digital data such as imageor pixel data/patterns. The specific optical data provided by the sensorreceiving module 212 may depend on the type of sensor being utilized.

In another configuration, the optical source may be a laser beam withhigh directivity and small divergence angle, and the optical sensor maybe either a single photodiode or an array of photodiodes or opticalsensors. The optical source may be driven by a driver or electric motorto sweep around the entire or large proportion of the growth surface112, and the single photodiode may also be driven by the same orseparate driver or electric motor to move with the source accordingly.This configuration may be useful for configurations in which differentregions of mold growth are defined. Each region may be scanned for thepresence of mold. The region in which mold is detected may be stored andmay indicate the type of mold that is present. The array of photodiodesor optical sensors may or may not need to move.

The optical source can be either single wavelength source or a sourcethat outputs multiple wavelengths (e.g., broad bandwidth source), andthe optical sensor may be either a narrow bandwidth or a broad bandwidthsensor accordingly. Optical property changes of the growth surface 112may be detected in the ultraviolet (UV) wavelength range, the visiblewavelength range or the infrared (IR) wavelength range depending on thespecific growth surface 112 and mycelium that is growing in the chamber103. If the optical source is a multi-wavelength or broadband source, anoptical spectrometer may also be used as the optical sensor to detectthe optical property changes in a spectra range. The spectra informationmay also contain mVOC or other information and both growth surface 112optical property changes and mVOC or other information change may bedetected in this way.

The optical source can also be an array of individual monochromaticoptical lasers. For example, ultraviolet lasers can induce fluorescencewhen illuminating the mold spores. With two or more ultraviolet lasersconfigured as the optical source and an optical spectrometer as theoptical sensor, the fluorescence of mold spores can be detected. Moldspores may be detected by signatures of fluorescence spectra.

The absorption, reflection and/or scattering change induced by moldgrowth may be detected directly by the light intensity received by thephotodetector. The color change induced by mold growth may be determinedusing a filter with a photodiode (or array), and RGB pixel (or RGB pixelarray). The control device 116 may incorporate algorithms to detectchanges in intensity and/or color.

In addition to growth in the plane of the growth surface 112, the moldmay grow out of the plane. A vertical depth of the mold may increase asthe growth time increases. The optical sensor may be configured as alaser-ranger finder (e.g., based on time-of-flight, frequency modulatedcontinuous wave, or structured-light technology) to detect theout-of-plane depth of the growing mold. The control device 116 may beconfigured to periodically measure the range finder to monitor thevertical growth of the mold. The control device 116 may compute a rateof change of the vertical growth.

The optical properties of the growth surface may be calibrated with areference before exposure to mold or mold growth and saved forcomparison with the optical properties observed after exposure andgrowth. The mold growth affects the optical properties within thechamber. By comparing the measurement results with baseline results, thecontrol device 116 may determine the presence of mold and the initialconcentration of mold.

Another technique for detecting the pH of the growth medium may be toutilize a pH meter such as a potentiometric pH meter. The growth mediummay include pre-printed electrodes for the potentiometric sensor. Thesurface above the electrodes may be coated with nutrients to promotemold growth. As the pH changes, the resistance measured between theelectrodes may change. The pH level may be determined by measuring theresistance between the electrodes. The control device 116 may beconfigured to receive the electrical signal and estimate the resistance.Electrical sensing is described in additional detail herein.

Another technique for detecting the pH may be to implement a system thatcontrols the pH of a small region of the growth medium. FIG. 19 depictsa configuration for controlling the pH of a surface. An active area ofthe growth surface 1902 may be covered by a hydro gel or similar coatingthat permits diffusion and promotes mold growth. The pH sensor mayinclude a sense electrode 1908 that is integrated with the growthsurface 1902. The sense electrode 1908 may have a proportionalelectrical potential response to pH with respect to a referenceelectrode 1912. A current source may supply current to one or moreworking electrodes (e.g., first working electrode 1904 and secondworking electrode 1906) which then flows through one or more counterelectrodes 1910. The control device 116 may control the current tomaintain the sensing electrode 1908 at a reference pH level 1916 thatmay be a constant pH value. This may be used to create a predeterminedpH environment to promote the growth of certain types of mold. This alsoprovides a feedback signal to provide a measure of the amount offeedback that must be applied to maintain the pH at a constant level. Anamplifier 1914 may receive inputs from the sense electrode 1908 and thereference electrode 1912. The output of the amplifier 1914 may beelectrically coupled to the control device 116. As the pH level of thegrowth surface 1902 changes due to mold growth, the amount of currentsupplied to the working electrodes 1904, 1906 may change. As a result,the voltage measured at the sense electrodes 1908 changes.

The configuration of FIG. 19 may be applied to create a certain pHenvironment that promotes growth of certain types of mold. The feedbacksignal from the sense electrode 1908 is proportional to an amount ofcurrent that must be applied to keep the pH constant. For example, if nomold is growing, the pH level should remain constant without changes tothe current. As mold grows on the surface, the pH level changes causingthe control device 116 to apply more current to rebalance the pH level.Mold growth may be detected by monitoring the feedback signal forchanges. If the feedback signal exceeds a predetermined threshold, moldmay be present. The growth surface may be configured with multiple areasconfigured as shown in FIG. 19. Each of the areas may be used to createa different pH environment for mold growth. In addition, different areasmay be configured to be in a different temperature zone (e.g., byoperating thermal control elements associated with each of the areas).In this manner, the environment may be configured to efficiently growdifferent types of mold.

Mold growing on the growth surface 112 may change electrical propertiesof the surface. For example, impedance, capacitance, frequency response,and/or other electrical properties of the growth surface 112 may bealtered due to mold growth. Properties of the growth surface 112 canchange due to mold growth as the mold feeds on the nutrients in thegrowth surface 112 and its roots (mycelium) spread to reach morenutrients. The changes in both the growth surface 112 and the intrusionof the mycelium cause changes in impedance, capacitance, frequencyresponse, and other electrical properties.

FIG. 14 depicts a sensing device configured to measure the electricalproperties. The electrical sensing configuration 1400 may include afirst electrical contact 1404 and a second electrical contact 1406 thatare coupled to a growth surface 1408. The first electrical contact 1404and the second electrical contact 1406 may be adhered or deposited onthe growth surface 1408. In some configurations, a substrate of thegrowth surface 1408 may be a film and the contacts may be deposited oretched onto the substrate.

A voltage may be applied across the first electrical contact 1404 andthe second electrical contact 1406. The voltage may create electricfields 1412 within the housing 1402 and the growth surface 1408. Thefirst electrical contact 1404 and the second electrical contact 1406 mayoperate as a capacitance sensor. A dielectric between the firstelectrical contact 1404 and the second electrical contact 1406 may bedefined by the growth surface 1408, mold 1410, and air with the housing1402. As the mold 1410 grows on the growth surface 1408 and into thechamber defined by the housing 1402, the dielectric properties maychange. By measuring the dielectric change over time, the system maydetect mold growth, concentration of mold, and/or types of mold. Thefirst electrical contact 1404 and the second electrical contact 1406 maybe electrically coupled to the control device 116. The control device116 may be configured to supply a voltage across the first electricalcontact 1404 and the second electrical contact 1406. The sensing devicemay include a current sensor to measure current flowing between thefirst electrical contact 1404 and the second electrical contact 1406.The control device 116 may be configured to generate an alternatingcurrent (AC) voltage waveform with a range of frequencies andmagnitudes. By applying a known voltage waveform and measuring theresulting current, the control device 116 may determine the capacitanceusing basic electrical relationships. As the mold 1410 grows and changesthe dielectric, the capacitance value may change. The control device 116may be configured to sweep the frequency to obtain a frequency responseof the dielectric properties.

FIG. 15 depicts a capacitive sensor 1500 that includes a plurality ofelectrical contacts 1504 that are coupled to or integrated with a growthsurface 1502. The electrical contacts 1504 may be arranged as a grid orother pattern. Each of the electrical contacts 1504 may be electricallycoupled to the control device 116 (e.g., by a matching grid ofelectrodes). The control device 116 may be configured to measure thecapacitance across any pair of electrical contacts 1504 as describedpreviously herein. The arrangement of the capacitive sensor 1500 allowsfor mold growth to be detected on different areas of the growth surface1502. By dividing the growth surface 1502 into smaller regions, moldgrowth may be determined in less time. The capacitive sensor 1500 canalso identify the specific region on the growth surface 1502 at whichmold is growing. This may be particularly useful when the growth surface1502 is configured with different nutrient treatments in differentregions (e.g., FIG. 8 and FIG. 10). The control device 116 may beconfigured to apply a voltage between any pair of contacts 1504 andmeasure a corresponding current. The control device 116 may identifymold growth between the pair of contacts when the capacitance changes bya predetermined amount.

FIG. 16 depicts a possible configuration for an electrical sensinggrowth medium 1600 for detecting electrical properties of a growthsurface 1602. The growth surface 1602 may include conductive strips thatcan be electrically excited to measure the electrical properties. Afirst conductive strip 1604 and a second conductive strip 1606 may beattached to the growth surface 1602. Between the first conductive strip1604 and the second conductive strip 1606 may be a mold growth area1608. The mold growth area 1608 may be treated with nutrients toencourage mold growth. Mold growing in the growth area 1608 may changethe electrical properties between the conductive strips. The conductivestrips may also be configured to be perpendicular to the depiction inFIG. 16. Other configurations of the conductive strips are possible(e.g., circular, arcs). The first conductive strip 1604 and the secondconductive strip 1606 may include periodic gaps 1605 or openings so thata measurement is only affected by the growth surface 1602 that is withinthe growth chamber.

FIG. 17 depicts a first electrical sensing configuration in whichelectrical contact with the conductive strips is via rollers of thesurface exchange mechanism. The electrical sensing configurations mayutilize a sensing device that is installed on a bottom-side of thegrowth surface 1602. The surface exchange mechanism may include a firstroller 1702 and a second roller 1704 that are in contact with theelectrical sensing growth medium 1600 while the growth surface 1602 iswithin the chamber 103. One or more of the first roller 1702 and thesecond roller 1704 may include conductive contacts about thecircumference of the corresponding roller. The conductive contacts mayextend around the milers so that the conductive contacts may contact theelectrical sensing growth medium 1600 at any rotational position of therollers. For example, the first roller 1702 may include a high-sidecontact 1706A that is electrically coupled to the control device 116.The first roller 1702 may include a low-side contact 1708A that iselectrically coupled to the control device 116. The second roller 1704may include a high-side contact 1706B that is electrically coupled tothe control device 116. The second roller 1704 may include a low-sidecontact 1708B that is electrically coupled to the control device 116.The high-side contacts 1706 on the rollers may be configured to alignwith the first conductive strip 1604 of the electrical sensing growthmedium 1600. The low-side contacts 1708 of the rollers may be configuredto align with the second conductive strip 1606 of the electrical sensinggrowth medium 1600. Electrical connection of the contacts 1706, 1708 tothe control device 116 may be through a slip ring or similar device.

As the growth surface 1602 of the electrical sensing growth medium 1600is advanced, the conductive strips may maintain contact with thecontacts of the rollers. The gaps 1605 may limit the measurement to thatsurface that is within the chamber. In this manner, the regions of thetape outside of the chamber do not affect the measurement. The controldevice 116 may measure the electrical properties of the electricalsensing growth medium 1600 by exciting the conductive strips. Forexample, the control device 116 may be programmed to apply a voltage orpotential across the high-side contact 1706 and the low-side contact1708. The voltage may cause a current to flow that is proportional tothe impedance of the mold growth area 1608. The control device 116 maymeasure the current that flows and can determine the resistance byapplication of Ohm's law. The control device 116 may supply an ACvoltage and sweep the frequency through a predetermined range to furthercharacterize the impedance and/or frequency response of the growth area1608.

For configurations having the conductive strips perpendicular to thosedepicted, the rollers may be constructed of a conductive material and beelectrically connected to the control device 116. The conductive stripsof the electrical sensing growth medium may be spaced at a distancecorresponding the distance between the rollers. In this configuration,one roller may contact a high-side conductive strip and the other rollermay contact the low-side conductive strip. The conductive strips mayfurther include gaps and the conductive surface of the rollers mayinclude corresponding gaps.

FIG. 18A depicts a second electrical sensing configuration 1800 thatrelies on electrodes to interface with the conductive strips in theelectrical sensing growth medium 1600. The second electrical sensingconfiguration 1800 may include a first electrode 1806 and a secondelectrode 1808. The first electrode 1806 and the second electrode 1808may be constructed of a conductive material and may be electricallyconnected to the control device 116. The first electrode 1806 may alignwith the second conductive strip 1606 of the electrical sensing growthmedium 1600. The second electrode 1808 may align with the firstconductive strip 1604 of the electrical sensing growth medium 1600. Theelectrical sensing growth medium 1600 may contact a first roller 1802and a second roller 1804 that are associated with the surface exchangemechanism.

FIG. 18B depicts a side view of the second electrical sensingconfiguration 1800 that provides more detail with respect to the secondelectrode 1808. The second electrode 1808 may be fit within an electrodehousing 1809. The electrode housing 1809 may be sized to partiallycontain the second electrode 1808 and allow movement of the secondelectrode 1808 toward and away from the electrical sensing growth medium1600. A spring mechanism 1810 (or other compliant element) may bepositioned in the electrode housing 1809 and under the second electrode1808. The spring mechanism 1810 functions to provide a force to thesecond electrode 1808 to maintain contact with the surface of theelectrical sensing growth medium 1600. The electrode housing 1809 may becoupled to a mounting surface 1812 that may be part of the surfaceexchange mechanism structure. Other electrodes may be similarlyconfigured. The first roller 1802 and the second roller 1804 may contactthe electrical sensing growth medium 1600 to facilitate movement. Thefirst roller 1802 and the second roller 1804 may also apply sufficientpressure to the electrical sensing tape 1600 to ensure that the chamberis sealed. The first roller 1802 and the second roller 1804 may becoupled to the mounting surface 1812 via brackets.

The control device 116 may be configured to measure a baseline impedancecharacteristic before mold grows on the growth surface. The controldevice 116 may then monitor for changes in the impedance characteristicsthat are indicative of mold growth. The control device 116 may storedata related to impedance characteristics for different types andconcentrations of mold. The control device 116 may compare measuredimpedance characteristics to the stored characteristics to identify atype of mold and/or concentration of mold within the chamber.

The electrical sensing configurations may further include features toenhance electrical contact between the conductive strips of the growthsurface and the sensing elements. For example, the electrical sensingconfigurations may include one or more magnets or electromagneticsarranged to magnetically attract the growth surface. For example, theconductive strips may be comprised of nickel. An electromagnet may bepositioned beneath the conductive strips near the electrode or roller(e.g., near where the electrical contact takes place) and energized whenelectrical contact is desired. The electromagnet may attract theconductive strip and ensure contact with the electrode or rollercontact. The feature is useful when the growth surface can be moved aselectrical contact may be broken during the moving process. Themechanism for reestablishing an electric connection between the growthsurface and sensing device ensures reliable performance.

In some configurations, mold may be detected using biological orchemical elements as a binding or reaction agent for sensing purposes.The biological or chemical elements may be configured to bind or reactwith mold spores. For example, certain antibodies or enzymes bind withcertain types of mold and binding events may be detected using varioussensing methods (e.g., change in electrical properties). Further, thereaction between the mold spores and the biological or chemical elementsmay cause the release of chemical compounds. The released compounds maybe detected with sensors such as chemical, optical, and electricalsensors. The binding or reaction event may be used to determine thepresence of different mold types. The binding or reaction agent may alsobe used to capture mold spores before the growth stage. Differentbiological or chemical elements may also be used to either promote orretard mold growth.

In some configurations, mold may be detected using an audio-basedsensing device. The growing mold may influence the manner that soundtravels within the chamber. Due to the mechanical nature of themolecular structure, growing mold will absorb and reflect sound waves ofcertain frequencies. In some configurations, the sensing device mayinclude a source configured to emit a sound wave and a receiverconfigured to convert the sound signals to electrical signals. Theconfiguration may depend on the type of sound to be measured. In aconfiguration that measures the reflection of the sound waves, a sourcemodule 210 and a receiving module 212 may be installed within thechamber (e.g., same side of growth surface). The receiving module 212receives sound waves that are reflected from the growth surface 112. Insome configurations, the sensing device may be an ultrasound transceiverthat includes the source module and receiving module. In a configurationthat measures the transmission of the sound waves through the growthsurface 112, the source module 210 and the receiving module 212 may bemounted on opposite sides of the growth surface 112 (e.g., depicted inFIG. 2). For example, the sensor source module 210 may be an ultrasoundspeaker and the sensor receiving module 212 may be a microphoneconfigured to convert sound signals to an electrical signal. The sensorsource module 210 may be driven by the control device 116. The controldevice 116 may operate the sensor source module 210 to output afrequency sweep in a predetermined range of frequencies. The controldevice 116 may receive the electrical signals from the sensor receivingmodule 212 and may measure the magnitude of the received sound signal.The control device 116 may be configured to estimate the molecularresonance frequency of the mold to determine the specific type of moldthat is growing.

The control device 116 may store previously generated sound profilesthat represent different mold types and concentration levels. Thecontrol device 116 may be configured to compare a measured sound profileto the stored sound profiles to identify a type and/or concentrationlevel of the mold that is growing in the chamber 103. In someconfigurations, the control device 116 may recognize mold growth by achange in the sound profile as compared to a baseline sound profile.Additional sensors may be incorporated (e.g., to measure volume orweight) to provide an improved estimation.

An ultrasound sensor may also be used to sense the out-of-plane growthof the mold by outputting a sound pulse and measuring the response time(e.g., time for sound to travel to the receiver). A larger verticalgrowth may result in a shorter return time of the pulse. The sensingdevice may include an ultrasound emitter and an ultrasound receiver tomeasure the response time. The control device 116 may include circuitryto generate the ultrasound signal and receive the reflected ultrasoundsignal. The control device 116 may include circuitry and/or controllogic to sense the delay between sending the ultrasound signal andreceiving the reflected signal. The control device 116 may be programmedto measure the height of the out-of-plane mold growth. The height may bemonitored over time and stored. The control device 116 may store dataregarding mold growth patterns for different types of molds. Forexample, mold growth patterns may be experimentally derived by testing.The mold type may be determined by comparing the measured growth patternto the historical patterns.

In configurations utilizing an audio-based sensing device, the enclosedvolume or chamber may be sound/audio isolated from the outside. Forexample, the chamber may be coated with a material to minimize soundecho. In addition, this prevent outside noise/sounds from disturbing themeasurement process within the chamber 103. The housing 102 may also beconfigured to optimize the audio/sound properties within the chamber 103to minimize unwanted echoes or reflections. An additional microphone maybe attached outside of the chamber 103 and be used to subtract externalnoises from the measurement signal to improve the accuracy of themeasurement (e.g., differential measurement).

The growth surface may also have certain mechanical properties (e.g.,inertia, mass). The surface may vibrate or oscillate when excited by asound wave. The vibration may be characterized by an amount of damping.The damping may be characterized as how quickly the magnitude of thevibration or oscillation dissipates after the excitation stops. Athicker layer of mold growth may result in more damping of the growthsurface. That is, the vibrations of the growth surface will dissipate isless time. The audio sensor source may be used to excite the growthsurface using sound waves to cause vibrations that may result in changesin the response times from the emitter to the receiver. A first baselinemay be established prior to exposing the growth surface to external airand a second baseline may be established prior to growing mold. Forexample, the audio signal may cause a vibration or deflections in thegrowth surface that may be measured. After exposure and mold growth, themeasurements may be repeated and compared to the second baseline. Anincrease in damping may be indicative of mold growth on the surface. Themagnitude of the increase in damping may be indicative of the amount ofmold growth that has occurred. Multiple ultrasound speakers may beemployed to create a stereo effect for measurements.

Experimental testing may be performed to determine the dampingproperties of mold growth in the chamber. Under controlled conditions,mold may be grown, and the damping properties may be measured atdifferent growth stages. The data may be stored for different types ofmold. The control device 116 may store the data for later comparison. Bycomparing a damping response to historical damping responses, thecontrol device 116 may be able to determine the stage of growth,concentration, and/or the type of mold that is growing.

Mold may be detected by measuring mechanical properties of the growthsurface that are changed by mold growth. The mechanical properties maybe measured by applying actuation pulses and measuring the resultingfrequency and/or amplitude responses. In some configurations, the moldsensor may include a mechanism for exciting the growth surface. Forexample, a piezoelectric substrate may be incorporated to facilitateexcitation of the growth surface. The growth surface and electricalcontact system may be configured similar to FIG. 16 through FIG. 18. Forexample, the growth surface may include a pair of conductive strips witha piezoelectric material between. The piezoelectric substrate may beelectrically coupled to the control device 116. Electrical contact maybe achieved as previously discussed herein using electrodes or contactson the rollers. The control device 116 may actuate the piezoelectricsubstrate (e.g., by applying a voltage or current at a predeterminedlevel or profile) to cause movement or deformation of the growth surfaceat a given frequency or amplitude defined by the excitation. The controldevice 116 may stop actuating the piezoelectric substrate and measurethe oscillation and/or damping. Measurement may be via an opticalsensing device or electrical sensing device. In some configurations, themeasurement may be performed using signals from the piezoelectricsubstrate. For example, the vibrations may cause a voltage across thepiezoelectric substrate.

The piezoelectric substrate may be used as a sensor for otherconfigurations such as the audio-based sensing configurations. Thepiezoelectric substrate may generate an electrical signal when pressurefrom the sound waves interacts with the piezoelectric substrate. Thepiezoelectric substrate may act as a microphone and may be used tomeasure the deflection or movement of the growth surface caused by soundwaves. The piezoelectric material may be disposed on thesubstrate/growth surface between at least two conductive regions. Thepiezoelectric material may be configured to generate an electricalsignal at the conductive regions based on a deflection of thesubstrate/growth surface. The piezoelectric material may be configuredto cause a deflection of the substrate/growth surface responsive to avoltage applied across the conductive regions.

The substrate may be structured as a cantilever, an array ofcantilevers, bridges, an array of bridges, a diaphragm or array ofdiaphragms, and a plate. In some configurations, independent mechanicalstructures may be configured to promote growth of different molds.Measuring the mechanical properties of each independent structure mayallow identification of the types of mold that are growing.

Excitation of the growth surface may also be achieved by anelectromagnet interacting with the growth surface. For example, aconductive strip of nickel or ferromagnetic material may be attracted tothe electromagnet. The control device 116 may be configured to pulse theelectromagnet to cause vibrations of the growth surface. An opticalsensor may then be employed to measure the oscillations and/or dampingof the growth surface. Mold growth may be determined by comparing theresponse to the first and second baseline responses taken during theinitial phases of the measurement cycle. Electrostatic actuation mayalso be applied to excite the growth surface. For example, a comb driveor electrostatic motor may be used to excite the growth surface.

The mold sensors may be configured for prolonged use for continuouslysensing mold in an environment. Such configurations may utilize thesurface exchange mechanism to continually advance the growth surface sothat multiple measurement cycles may be performed. In someconfigurations, the surface exchange mechanism may be an interchangeablecartridge that permits a new growth medium to be installed to continuetesting. Some sensor configurations may be well suited for aninterchangeable configuration. For example, configurations in which thesensing device is incorporated into the housing may be well-suited forthese applications. Configurations that include part of the sensingdevice below the growth surface may require additional cost for eachreplacement cartridge.

The surface advancement mechanism may be configured to identify a lackof availability of a new growth surface. For example, the tape-basedsurface exchange mechanism of FIG. 11 may not be able to advance thegrowth surface when there is no more unused tape. This may be detectedby an increase in torque or inability to change the speed of the drivenspool 1106. The control device 116 may be configured to detect this andnotify the user that additional measurements are not possible. In otherconfigurations, the last growth surface that can be moved to the chambermay be given different properties. For example, last growth surface maybe given a different characteristic that may be recognized by thesensing device. For example, the last growth surface may be transparentor mirrored to change the intensity of light detected by an opticalsensor. The control device 116 may be configured to detect the changeduring a baseline measurement and flag the condition.

The mold sensor may also be configured as a one-time use device todetect mold a single time. The mold sensor may be configured with aninterchangeable cartridge that does not advance the growth surface. Theone-time use application may be better suited to some sensorconfigurations such as variants that measure the mechanical properties.For example, the mold sensor may define a slot that permits a growthsurface (e.g., a slide or strip) to be inserted manually. Uponcompletion of the measurement cycle, the growth surface may be manuallyremoved and discarded. In some configurations, the growth surface may becleaned and retreated with nutrients and reused.

In some configurations, a continuous measurement configuration may beconfigured to clean and retreat the growth surface. For example, atape-based configuration may include an electromechanical wiper/scrapermechanism that scrubs the growth surface after the mold destructionphase. The surface exchange mechanism may be configured with a removablewaste bin that collects the waste. The surface exchange mechanism may beconfigured to reapply nutrients on the growth surface. For example, thegrowth surface may be moved through a reservoir of nutrients or anutrient solution may be sprayed or dripped onto the growth surface.

The sensing device configurations described herein may be combined in agiven application. The mold sensor may utilize more than one of thesensing technologies described to better measure the mold growth ordifferent properties that are indicative of mold growth.

The growth of mold and the rate of mold growth may be affected bytemperature. Different types of mold may have different responses to agiven temperature. Referring again to FIG. 1, the thermal controlelement 120 may be controlled by the control device 116. The thermalcontrol element 120 may be operated to influence the growth of moldwithin the chamber 103. The control device 116 may implement aclosed-loop temperature control within the chamber 103 by controllingthe thermal control element 120 with temperature feedback from thechamber environment sensor 118. The control device 116 may be configuredto select a temperature setpoint to optimize mold growth within thechamber 103 for a given type of mold. The control device 116 may beconfigured to adjust the temperature setpoint to detect the presence ofdifferent types of mold. An open-loop strategy may also be implementedin which the control device 116 is programmed to activate the thermalcontrol element 120 with a predetermined profile.

The control device 116 may be configured to operate the mold suppressor108 to influence mold growth. The control device 116 may operate themold suppressor 108 to determine a strength of the mold. The controldevice 116 may operate the mold suppressor 108 in short bursts that areconfigured to kill weaker mold spores. The control device 116 mayoperate the mold suppressor 108 to modulate the growth rate of the mold.The control device 116 may further operate the mold suppressor 108 toprevent saturation of the chamber 103 by destroying some of the mold.The control device 116 may be configured to perform sensor measurementsbefore and after application of the mold suppressor 108 to identifydifferences in the mold concentration that may have occurred. Thecontrol device 116 may be configured to identify a rate of molddestruction during activation of the mold suppressor 108. The rate ofmold destruction may be used to identify the type of mold that isgrowing.

The mold suppressor 108 may be configured to output different UVwavelengths to measure the effect of the different UV wavelengths onmold destruction. The mold suppressor 108 may be configured such thatthe intensity of light may be varied. The control device 116 may controlor select the intensity of the light and the UV wavelength during themold destruction phase. The control device 116 may operate differentlight sources that provide different wavelengths of light or filterelements with one or more broadband light source. When the controldevice 116 has determined that a particular type of mold is present, thecontrol device 116 may be configured to select a UV wavelength that iseffective for destroying the particular type of mold that is present.The control device 116 may store data regarding the preferred parametersfor the mold suppressor 108 for destroying different types of mold.

The mold sensors described may be operated automatically. For example,the control device 116 may be configured to schedule a measurement cycleat predetermined time intervals. The control device 116 may beconfigured to determine trigger conditions for initiating a measurementcycle. For example, the control device 116 may monitor weatherinformation from the external sensors or network to determine ifconditions are present for mold growth. For example, the control device116 may initiate a measurement cycle after detecting an increase inhumidity or a decrease in temperature. The control device 116 may alsobe configured to learn local conditions that result in an increased riskof mold growth. The control device 116 may store measurement results andthe associated conditions during the measurement cycle. Over time, thecontrol device 116 may learn that certain conditions are associated withmold growth. When the conditions are detected, the control device 116may reduce the time between measurement cycles.

FIG. 20 depicts a possible configuration of the mold sensing system. Amold sensor 2000 may include the control device 116. The control device116 may include a processing unit 2002 and volatile and non-volatilememory 2004. The mold sensor 2000 may include a Human-Machine Interface(HMI) 2008 for interacting with the user. The HMI 2008 may be acombination of hardware and software elements. The mold sensor 2000 maybe operated on demand by the user. The control device 116 may implementthe HMI 2008 (e.g., button/light) that permits the user to initiate ameasurement cycle. The user may initiate a measurement cycle by pressinga button and a light may indicate that a measurement cycle is inprogress. The mold sensor 2000 may further include an alarm 2014 thatprovides feedback if mold growth threshold is sensed. The alarm 2014 maybe a visual alarm such as a light-emitting diode (LED) or display panel.In some configurations, the alarm 2014 may be an audible alarm. Thecontrol device 116 may be programmed to activate the alarm 2014 via theHMI 2008 in response to detecting mold concentrations exceeding athreshold during a measurement cycle. The control device 116 may detectgreater than normal mold growth when an estimated mold concentrationexceeds a predetermined concentration. The alarm may be an audible alarmand/or a virtual alarm that is communicated to the user.

The control device 116 may include a communication interface 2006 thatallows a user to communicate with the control device 116 via a cloud ornetwork 2010 (e.g., Ethernet, Bluetooth). The control device 116 may beprogrammed with a web interface that allows access to the mold sensorparameters via a web browser on a user device 2018 such as a computer orother device. The HMI 2008 may include an application running on theuser device 2018 which may be a cell phone or tablet. The HMI 2008 maybe configured to permit the user the initiate and/or schedule ameasurement cycle. The HMI 2008 may be configured to communicatemeasurement results to the user. The HMI 2008 may be configured toinform the user about the current status of the mold sensor. Forexample, the HMI 2008 may communicate the remaining battery life, growthsurface or measurement cycles remaining, and warnings related to molddetection. The mold sensor 2000 may include a display module that isdriven by the HMI 2008.

The mold sensor 2000 may include a power interface 2016 for providingpower to the mold sensor components. The power interface 2016 mayinclude a battery. The battery may be rechargeable. In someconfigurations, the power interface 2016 may provide a coupling to anexternal source. For example, power may be provided by a power supplythat connects to a household power outlet.

The system may include a plurality of mold sensors 2000 that workcooperatively to determine mold growth and concentrations. In someconfigurations, the mold sensing system may include a first mold sensor(e.g., 2000A) and a second mold sensor (e.g., 2000B). The first moldsensor 2000A may be located in an area for which excessive mold growthis to be monitored. The second mold sensor 2000B may be located in areference area. For example, the reference area may be outdoors. Thereference area may be an area in which excessive mold growth is notsuspected. The second mold sensor 2000B may provide information on moldconcentrations that are normally present in the environment. Forexample, the second mold sensor 2000B may provide mold growthinformation for a normal amount of mold spores that are naturallypresent in the environment. The first mold sensor 2000A may provideinformation on mold concentrations that may be different from thereference area due to being located in an area of active mold growth.For example, the first sensor 2000A may be located in a damp basement inwhich mold has been growing for some time. The presence of mold in anenclosed area may result in an increased concentration of mold spores inthe air when compared to the reference area. By using multiple moldsensors, the system may determine if the concentration of mold isabnormal relative to the reference area.

Using multiple mold sensors may prevent inaccurate assessments. Forexample, mold spore concentrations may normally vary during the year. Byinclude a reference mold sensor, the normal variations may be subtractedout from the mold assessments of interest. This provides more accurateconcentration data for the area of interest and may prevent falsewarnings due to seasonal variations in mold spore concentrations. Forexample, the mold sensing system may inhibit a warning when a ratio ofthe measured mold concentration to the reference mold concentrationratio is less than a threshold. A warning may be indicative that thereare more mold spores of certain types on an inside area when compared toan outside area.

In some configurations, the system may evaluate mold growth fordifferent types of mold. For example, a growth surface havingdifferently treated regions and/or a growth surface having regionsexposed to different environmental conditions may grow different typesof mold. The sensor may be configured to measure the concentration ofmold for each region or type of mold. The concentrations of each type ofmold may be compared to corresponding reference values from a moldsensor placed in a reference area.

The mold sensors 2000 may communicate with one another via thecommunication interface 2006. One of the mold sensors 2000 may beconfigured as a master device. The master device may be configured tomanage and coordinate the operation of the other mold sensors. Themaster device may receive mold growth and concentration data from theother mold sensors. The master device may synchronize measurement cyclesof the mold sensors 2000. For example, the master device may send astart measurement cycle signal to the mold sensors to initiate ameasurement cycle. The master device may be further configured todetermine the mold growth concentration threshold based on data from areference mold sensor.

The control device 116 may be configured to perform data analysis. Thecontrol device 116 may be further configured to collect measurement dataand send the data to a server 2012 or cloud computer for processing. Thecontrol device 116 may be configured to send measurement data to theuser device 2018. An advantage to external processing is that algorithmsmay be changed in a central location without the need for reprogrammingeach individual mold sensor. Over time, the algorithms may be improved.In addition, data from many mold sensors can be analyzed to developimproved mold sensing strategies as well as better characterize moldgrowth.

The user device 2018 may be programmed to coordinate the operation ofmultiple mold sensors 2000. For example, a program may be executed onthe user device 2018 that allows the user to establish communicationwith the mold sensors 2000. The program may allow the user to identifythe mold sensors 2000. For example, the program may allow identificationof one of the mold sensors as the reference mold sensor. The program maydetermine mold alert thresholds based on the data received from thereference mold sensor. The control device 116 may communicate resultsvia the Internet to the user device 2018. This allows placement of themold sensors 2000 with the capability of remote monitoring. In addition,the program may allow for any number of mold sensors to be added to amold sensing system.

The mold sensors 2000 may include self-testing capabilities. The controldevice 116 may be programmed to operate the components to provideconfirmation of proper operation. For example, the control device 116may be configured to detect that the air entry portal 104 is operatingproperly. Some configurations may include an electric switch or contactthat closes when the air entry portal 104 is in a predeterminedposition. The control device 116 may actuate the air entry portal 104and monitor the switch or contact to verify proper operation.

The control device 116 may be configured to operate the mold suppressor108 to confirm proper operation. For example, in configuration with anoptical sensing device, the control device 116 may activate the moldsuppressor 108 and confirm operation by sampling the optical sensingdevice.

The control device 116 may be further configured to calibrate thesensing system. The control device 116 may be configured to check thesensor status under conditions in which no mold is growing in order toestablish a baseline condition. The control device 116 may check thesensing device prior to exposing the growth surface to the air and/orimmediately after exposing the growth surface to air. The resultingsignal should be indicative of no mold growth. If the sensing deviceprovides signals that are indicative of mold growth, the mold sensor mayrequire service or need cleaned.

The mold sensor may be used to estimate the mold spore concentration.When the mold sensor is configured with predetermined fixed parameters(e.g., temperature, humidity, pressure, measurement time period), theconcentration of mold spores detected in the volume may be correlatedwith the mold spore concentration from the reference area. For example,mold growth data may be determined to correlate the measured parameterwith the concentration of mold. Such a feature may be useful in thedesign of multi-chamber mold sensors for detecting certain types ofmold.

The measurement time may be reduced and detection accuracy improved byimplementing mold growth curve fitting and/or pattern recognitionalgorithms. Mold grows differently in different environments. Curvefitting or pattern recognition may be achieved by changing one of theparameters (e.g., temperature, humidity, pressure) during themeasurement. The sensing device may be monitored to determine how themeasured properties change in response to the change in the parameter.For example, if the sensor output changes more rapidly at higherhumidity than at lower humidity, mold spores may exist. This allows molddetection without having to wait for mold spores to grow to largeconcentrations.

FIG. 21 depicts a flowchart 2100 for a possible sequence of operationsfor operating the mold sensor configurations. At operation 2102, a checkmay be performed to determine if a measurement trigger condition ispresent. For example, the measurement may be manually triggered by abutton or switch, commanded via the network, and/or scheduled. In someconfigurations, the control device 116 may determine a trigger conditionbased on environmental conditions. The trigger conditions may include acheck to determine that there is sufficient growth surface available toperform the measurement (e.g., tape remaining exceeds amount needed formeasurement). If there is not trigger condition, operating 2102 may berepeated.

If the measurement trigger condition is satisfied, operation 2104 may beperformed to position the growth surface. A measurement cycle may beginby first positioning an unused portion of the growth surface to aposition at which it can receive airflow. In configurations with amovable growth surface, the control device 116 may actuate the surfaceexchange mechanism to advance the growth surface to a predeterminedposition. For example, an unused portion of the growth surface may beadvanced into the growth chamber. In some configurations (e.g., FIGS. 6and 7), the growth surface may be positioned in an exposed regionoutside of the growth chamber.

At operation 2106, the growth surface may be exposed to air. Forexample, the control device 116 may open the air entry portal to permitairflow into the growth chamber. The air entry portal may be opened fora predetermined time period and then closed. The predetermined timeperiod may be determined based on environmental conditions detected fromthe environment sensors. In some configurations, an airflow sensor orpressure sensor may be monitored to determine when to close the airentry portal.

At operation 2108, a baseline measurement of the particles that attachedto the growth surface may be performed. Prior the baseline measurement,the air entry portal may be closed. The baseline measurement may dependon the type of sensing technology being used. For example, in agas/chemical sensor configuration, mVOCs in the closed chamber may besensed and recorded. For an optical sensor, the properties oflight/electromagnetic waves reflected from or transmitted through thegrowth surface may be measured.

If there are mold spores attached to the nutrient-rich growth surface,mold will begin to grow. At operation 2110, the chamber environment maybe controlled to predetermined parameters. The control device 116 may beconfigured to enhance the growth environment by operating the thermalcontrol element(s) 120. The control device 116 may operate the thermalcontrol element 120 to increase the speed of mold growth. In addition,any additional system for promoting mold growth may be activated (e.g.,humidity control).

At operation 2112, sensor measurements may be performed. The controldevice 116 may make measurements using the one or more sensing devicesduring the growth period and compare the results to the baselinemeasurement. For example, the control device 116 may monitor the changein mVOCs during the growth period. For an optical sensor, the propertiesof reflected or transmitted light may be monitored.

At operation 2114, a check may be performed to determine if themeasurement cycle is completed. For example, a measurement cycle may becomplete after a predetermined duration. In some configurations, thesensor data may be monitored and the measurement cycle may be terminatedif mold growth is detected. If the measurement cycle is not complete,operation 2112 and operation 2114 may be repeated.

If the measurement cycle is completed, operation 2116 may be performedto process the sensor data. The presence of mold may be determined bycomparing the sensor data to stored data that is indicative of moldgrowth. The amount of mold growth may be back-calculated to determinethe concentration of mold spores using algorithms such as QuantitativePolymerase Chain Reaction (QPCR). The processed measurements may includethe mold detection data from other mold sensors coupled within the samecommunication network. A mold concentration from a reference sensor maybe compared to the other measured mold concentrations. The controldevice 116 may be programmed to change a signal indicative of moldgrowth based on changes detected in the sensor measurements. Forexample, the control device 116 may make periodic measurements andcompare the results to the baseline measurements.

At operation 2118, a check may be performed to determine if mold isdetected as described previously herein. For example, if the ratio ofthe measured mold concentration to a reference mold concentrationexceeds a threshold, the system may indicate that mold is present. Ifmold is detected, operation 2120 may be performed to generate an alarmor warning signal. A signal indicative of mold growth may be generatedand output. The alarm or warning may be sent to and displayed on theuser device 2018. After generating the warning or indication, operation2122 may be performed. If no mold is detected, operation 2122 may beperformed. The signal indicative of mold growth may be an indicator thatmold growth has been detected in a sample. In some configurations, thesignal indicative of mold growth may be an indicator that an amount orratio of mold in the air exceeds a predetermined threshold. In someconfigurations, the signal indicative of mold growth may be anindication of a measure of the amount of mold present in the sample orthe air.

At operation 2122, the control device 116 may operate the moldsuppressor to destroy any mold that may have grown. The control device116 may sample the sensing device during the destruction phase to detectany changes to ensure that the mold is being destroyed. The entireprocess may then be repeated.

The mold sensor configurations provide that ability to monitor moldgrowth in an environment over time. The enclosed volume provides acontrolled environment for mold growth that allows for more rapiddetection of mold. In addition, the enclosed volume allows mold growthwithout allowing the mold to spread to other areas. Further, after themeasurement cycle, the mold suppressor can be activated to destroy themold that was grown. The surface exchange mechanism permits the growthsurface to be exchanged to enable additional measurement cycles. Themold sensor permits continuous monitoring of an area for a period oftime.

Some configurations of the growth surface may permit identification ofthe type of mold that is growing. The sensing device may be configuredto measure mold growth in a particular region of the growth surface. Inthis manner, the mold sensor may determine the type of mold that isgrowing. The mold detection device is configured to grow mold from moldspores that are present in the air at the time of sampling. The deviceis configured to deduce or back-calculate to determine the concentrationof mold spores in the air that was sampled.

The mold detection device may be used in a variety of manners. In someapplications, the mold detection device may be used to determine anabsolute measurement of the mold concentration. In other applications,the mold detection device may be used to indicate if the moldconcentration exceeds a threshold that is indicative of a mold issue(e.g., threshold mold sensor). In some applications, the mold detectiondevice may be configured to provide a yes/no indication of a presence ofmold. The mold growth rate on the growth surface depends on the quantityof mold spores inoculated on the growth surface. The inoculation iscorrelated to the concentration of mold spores in the air. The molddetection device may be placed in an environment for a predeterminedduration of time. The mold detection device may be configured such thatthe detection of mold growth at the end of the time duration isindicative of the concentration of mold spores in the sampled air beingabove a threshold. The threshold may be selected to indicate a moldissue in the environment in which the mold detection device is placed.If there is no detection of mold growth at the end of the time duration,the concentration of mold spores in the sample air is less than thethreshold and is indicative of the absence of a mold issue.

The threshold mold sensor may be configured to target a predeterminedtype of mold. For example, the nutrient platform may be configured topermit the growth of the predetermined type of mold. Nutrients may beadded to the growth surface that favor growth of the predetermined typeof mold.

In other examples, the mold sensor may be configured to target aplurality of mold types. In these configurations, the growthrelationships between the plurality of mold types may be investigatedand understood. For example, the growth or presence of one type of moldmay inhibit the growth of a second type of mold. Understanding therelationship allows the mold sensor to be constructed to minimize suchconditions. In addition, the environmental parameters such astemperature and humidity may be controlled to encourage mold growth.

The processes, methods, or algorithms disclosed herein can bedeliverable to/implemented by a processing device, controller, orcomputer, which can include any existing programmable electronic controlunit or dedicated electronic control unit. Similarly, the processes,methods, or algorithms can be stored as data and instructions executableby a controller or computer in many forms including, but not limited to,information permanently stored on non-writable storage media such as ROMdevices and information alterably stored on writeable storage media suchas floppy disks, magnetic tapes, CDs, RAM devices, and other magneticand optical media. The processes, methods, or algorithms can also beimplemented in a software executable object. Alternatively, theprocesses, methods, or algorithms can be embodied in whole or in partusing suitable hardware components, such as Application SpecificIntegrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs),state machines, controllers or other hardware components or devices, ora combination of hardware, software and firmware components.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms encompassed by the claims.The words used in the specification are words of description rather thanlimitation, and it is understood that various changes can be madewithout departing from the spirit and scope of the disclosure. Aspreviously described, the features of various embodiments can becombined to form further embodiments of the invention that may not beexplicitly described or illustrated. While various embodiments couldhave been described as providing advantages or being preferred overother embodiments or prior art implementations with respect to one ormore desired characteristics, those of ordinary skill in the artrecognize that one or more features or characteristics can becompromised to achieve desired overall system attributes, which dependon the specific application and implementation. These attributes caninclude, but are not limited to cost, strength, durability, life cyclecost, marketability, appearance, packaging, size, serviceability,weight, manufacturability, ease of assembly, etc. As such, to the extentany embodiments are described as less desirable than other embodimentsor prior art implementations with respect to one or morecharacteristics, these embodiments are not outside the scope of thedisclosure and can be desirable for particular applications.

What is claimed is:
 1. A mold sensor comprising: a housing defining achamber; a substrate treated to promote mold growth and exposed withinthe chamber; a sensing device configured to measure a property of thesubstrate that corresponds to a pH value of the substrate; and acontroller programmed to receive measurements of the property from thesensing device, generate an estimated pH value of the substrate from themeasurements, and output a signal indicative of mold growth on thesubstrate responsive to the estimated pH value being associated withmold growth.
 2. The mold sensor of claim 1, wherein the substrate istreated with a pH indicator that changes color as the pH value of thesubstrate changes due to mold growth.
 3. The mold sensor of claim 2,wherein the property is a color of the substrate and the sensing deviceis a camera configured to generate color images of the substrate, andthe controller is further programmed to process the color images andgenerate the estimated pH value of the substrate based on the colorderived from the color images.
 4. The mold sensor of claim 1, whereinthe property is an impedance of the substrate and the sensing deviceincludes a plurality of electrodes attached to the substrate, and thecontroller is further programmed to generate the estimated pH value ofthe substrate based on the impedance between pairs of electrodes.
 5. Themold sensor of claim 1, wherein the sensing device includes a senseelectrode, a reference electrode, and a working electrode attached tothe substrate.
 6. The mold sensor of claim 5, wherein the controller isfurther programmed to supply a current to the working electrode suchthat a voltage at the sense electrode remains at a predetermined voltageand generate the estimated pH value of the substrate based on thecurrent.
 7. The mold sensor of claim 6, wherein the controller isfurther programmed to supply the current to maintain a pH value at apredetermined pH level.
 8. A mold sensor comprising: a housing defininga chamber; a substrate coated with a hydrogel that includes nutrients topromote mold growth and exposed within the chamber, at least oneelectrical sense device including a sense electrode, a referenceelectrode, and a working electrode embedded in the hydrogel; and acontroller programmed to supply a current to the working electrode suchthat a voltage at the sense electrode remains at a predetermined voltageand estimate a pH value of the hydrogel based on the current.
 9. Themold sensor of claim 8, wherein the controller is further programmed to,output a signal indicative of mold growth in the chamber based onchanges in the estimate of the pH value.
 10. The mold sensor of claim 8,wherein the controller is further programmed to supply the current tomaintain the pH value at a predetermined pH level.
 11. The mold sensorof claim 10, wherein the predetermined pH level is configured toencourage growth of one or more predetermined types of mold.
 12. Themold sensor of claim 8, wherein the substrate is segmented into aplurality of zones and there is at least one electrical sense device ineach of the zones.
 13. The mold sensor of claim 12, wherein thecontroller is further programmed to maintain the pH value of the zonesat a different pH level.
 14. The mold sensor of claim 8, wherein thecontroller is further programmed to change the current to maintain thesense electrode at a predetermined reference voltage representing apredetermined pH value.
 15. The mold sensor of claim 8, wherein thecontroller is further programmed to generate a signal indicative of apresence of mold growth responsive to the current exceeding apredetermined current.
 16. A method comprising: supplying, by acontroller, a current to a working electrode attached to a substratecoated with a hydrogel such that a voltage at a sense electrode attachedto the substrate remains at a predetermined voltage; estimating, by thecontroller, a pH value of the hydrogel based on the current; andoutputting, by the controller, a signal indicative of mold growth on thehydrogel based on the pH value that is estimated.
 17. The method ofclaim 16 further comprising supplying the current to maintain the pHvalue of the hydrogel at a predetermined pH value.
 18. The method ofclaim 17, wherein the predetermined pH value is configured to encouragegrowth of one or more predetermined types of mold on the hydrogel. 19.The method of claim 16 further comprising adjusting the current based ona difference in voltage between the sense electrode and a referenceelectrode attached to the substrate.
 20. The method of claim 16 furthercomprising measuring the current prior to mold growth to establish abaseline pH level.